feat(studio): instrument the audio FX rack, including work an agent did (#3229)

* fix(studio): close the typecheck and fallow gaps wa-18b-reschedule opened

useAutomationLanes.ts's write() assumed gesture-scoped coalescing and a
preview-only commit that useDomEditAttributeCommits.ts never grew — backported
that option support from its own later commit so the two sides of the API
agree. The paste path and its tests were missing the box selection's v0/v1
bounds a sibling commit added to AutomationSelection. The FX panel's carve
controls still edited the six mechanism numbers (maxCutDb, bands,
intelligibilityBias) after carveProfile() collapsed authoring to one Strength
knob, so those fields no longer existed on HfCarveSettings; UI now edits
strength, and analyseCarveBands is called with carveProfile(strength).

Also closes fallow's complexity, dead-code and duplication findings on this
PR's diff: extracted automationLaneDragMath.ts (pure group/point-move math)
and useAutomationRangeDrag.ts (the marquee-select gesture) out of
useAutomationLaneGestures.ts, pulled a couple of render-loop ternaries and a
resolver into named functions, dropped an export nothing outside its file
used, and shared a step-simplifier between audioCarve's two envelope
builders.

The edge-stretch vs. box-select priority test in TimelineAutomationLane.test
was still pinning the pre-box-select rule (edge wins over a point sitting on
it) that a sibling commit deliberately reversed — a point inside the box is
now selected content, so grabbing it drags the group instead. Updated the
test to the shipped rule instead of the old one.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* fix(core): cap the via conic's weight so an edge-clamped via point can't NaN

A via point pulled out past the segment (viaX: 5, viaY: -3) clamps to
(0.999, 0.001) — exactly on the steady region's edge, where edge - viaX is 0.
viaConic divided by that zero to get an infinite weight, and shapeVia turned
Infinity into NaN a few steps later (Infinity - Infinity in the quadratic
coefficient). NaN reaching setValueCurveAtTime silences the automated
parameter for the rest of the render.

Capped the weight at 1e6 instead of leaving it unbounded — past that point
the arc already reads as touching the via point, so nothing visible is lost.
Also hardened shapeVia's existing denominator guard (`<= 0`) to `!(> 0)`,
since NaN fails the original comparison and fell through it.

Review by Miga (PR #3208).

* fix(studio-server): fingerprint the proactive waveform cache key too

The route already keys the waveform cache on the asset's size and mtime as
well as its path, so a rebuilt-in-place file gets fresh peaks instead of
stale ones. generateWaveformCache — the proactive path that runs on upload —
still called buildWaveformCacheKey with the path alone, so it wrote to a
different key than the route reads from (making the pre-generated cache
never found) and kept the exact collision bug this fingerprint exists to fix
on its own path.

Review by Miga (PR #3211).

* style(docs): run oxfmt on the /hyperframes-audio skill docs

Table column widths had drifted out of alignment with oxfmt's own rules,
failing format:check and blocking the Preflight gate every downstream
branch inherits. Whitespace only, no content change.

* fix(core): stop \b from missing underscore-separated names, guard clipsOverlap's negative duration

\b treats `_` as a word character, so \bbed\b never matched bed_01,
music_bed_loop, or theme_song, and \bvo\b/\bvox\b/\btts\b had the same gap —
an underscore-separated bed classified as "unknown" and could end up offered
as its own carve source. Replaced the short hints with a boundary that
actually excludes letters and digits on both sides.

clipsOverlap computed end = start + duration without guarding sign, so a
negative duration put end before start — an interval that does not describe
anything, and one specific case showed it silently dropping a real overlap
(a shorter, earlier broken end rejected a clip that genuinely contained the
point). Duration clamps to zero instead: a clip cannot un-play time, and a
zero-length clip at its start is the sane reading of "duration nobody wrote
down as positive."

Review by Miga (PR #3212).

* fix(studio): widen PropertyPanel's resetModules render timeout again

The 20s margin (already once widened for the same reason) is timing out in
CI's full-monorepo Test run — the resetModules()+fresh-import render this
test needs is uncached and competes with every other package's test suite
for the same worker pool, and the same test passes in well under 2s
standalone. Went to 45s rather than re-tuning to whatever number happens to
clear the current CI load, since that number moves every time CI gains a
package.

* fix(studio): stop the single-candidate auto-apply carve firing twice

Two auto-apply effects both fire when sourceOptions.length === 1: the
multi-candidate effect only guards length === 0, so a single candidate
passes it too, and the single-candidate effect passes its own guard right
after — both compute the same sources list and both call setCarve, so the
common case (one narrator, one bed) triggered two decodes, two FFT runs, and
two concurrent attribute writes for one decision.

The multi-candidate effect now defers to its sibling for exactly one
candidate, which already has its own detailed handling for that case.

Review by Miga (PR #3213).

* feat(core): carve against every voice over a bed, always (#3212)

* feat(core): carve against every voice over a bed, always dynamically

A bed usually runs under a whole sequence — a narrator, an interview answer, a
second presenter — and carving against one of them left the others fighting it.
`source` becomes `sources`, and `mixCarveSources` sums every voice onto the BED's
clock before anything is measured. That is what keeps one analysis sufficient: the
chain is fixed, so there is no per-voice filter to switch between, and bands drawn
from all the speech there is with envelopes that rise wherever any of it happens
answer the actual question — where and when is speech masking this bed.

Summed rather than averaged: two people talking at once mask more than either
alone. Audio before the bed starts is dropped rather than folded in at zero, since
it plays over nothing and shifting it would put a cut where there is no voice.

`dynamic` is gone. A fixed depth thins the bed through every pause, and once both
have been heard there is no reason to want it, so every carve follows the speech.

Two helpers the panel and the headless script now share instead of each carrying a
copy — two definitions of "what does this name suggest" drift, and then the two
disagree about which track is the voice:

- `classifyAudioName` reads a track's kind from its id and filename together.
  `unknown` is deliberately common: treating an unrecognised name as "not a voice"
  would hide the one track somebody needs to pick.
- `clipsOverlap` keeps out a voice that never plays while the bed does. An unwritten
  duration counts as unbounded, not zero — refusing a clip whose length the
  composition leaves to the media would drop the commonest case there is.

Files written before this still load: a single `source` reads as a one-voice list,
a stored `dynamic` is ignored, and an absent attribute means the defaults whole.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

* fix(core): stop \b from missing underscore-separated names, guard clipsOverlap's negative duration

\b treats `_` as a word character, so \bbed\b never matched bed_01,
music_bed_loop, or theme_song, and \bvo\b/\bvox\b/\btts\b had the same gap —
an underscore-separated bed classified as "unknown" and could end up offered
as its own carve source. Replaced the short hints with a boundary that
actually excludes letters and digits on both sides.

clipsOverlap computed end = start + duration without guarding sign, so a
negative duration put end before start — an interval that does not describe
anything, and one specific case showed it silently dropping a real overlap
(a shorter, earlier broken end rejected a clip that genuinely contained the
point). Duration clamps to zero instead: a clip cannot un-play time, and a
zero-length clip at its start is the sane reading of "duration nobody wrote
down as positive."

Review by Miga (PR #3212).

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

* fix(studio): port the carve UI off the removed source/dynamic fields

#3212 (accidentally squash-merged into this branch instead of main) changed
HfCarveSettings from a single `source` + `dynamic` toggle to a `sources`
list with dynamic mode removed outright — the multi-voice UI consumer that
goes with that shape lands in the very next PR, so this branch was left with
a type that no longer matched its own code.

Minimal port, not the multi-voice redesign that PR does properly: the
"Listen to" picker and analyse() treat sources[0] as the one voice this UI
still understands, and every dynamic-mode branch (the automated envelope
lanes, the toggle, the checkbox) is gone along with the field — a carve is
now always the static value the analysis computes, matching what the type
change made permanent. Test suite trimmed the same way: the automation-lane
and toggle tests covered behavior that no longer exists.

* refactor(studio): break up the FX rack's largest functions and files

Fallow flagged 9 complexity findings and 2 file-size violations after the
telemetry stack landed. Extracts FxPresetRun, FxAddMenu, FxRackChain,
FxNodeOpenBody, FxNodeParams, and useFxAudition/useFxCarve/useFxLevelling/
useFxChainObserved out of propertyPanelFxSection.tsx and
propertyPanelAudioFxGroup.tsx, splits propertyPanelFxNodeRow.tsx's open-face
rendering into its own component, and dedupes a clone in studioTelemetry.ts.
Pure structural move — no behavior change; full test suite still green.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

skills/hyperframes-audio/references/diagnosis.md

@@ -0,0 +1,241 @@
+# Diagnosing audio you cannot hear
+
+The symptom table in `SKILL.md` starts from "it sounds boomy". That presumes
+somebody already listened and said so. Handed a file and "fix this", you have
+no such sentence — and you cannot listen. This is how to get one.
+
+It is worth being blunt about the difficulty first, because the failure mode is
+not "no answer", it is **a confident wrong answer**:
+
+> **The absolute spectrum of a single unknown voice cannot be diagnosed.**
+
+Every voice has peaks and dips of exactly the size an injected filter has.
+Formants are ±10 dB. A speaker's fundamental sits anywhere from 85 to 255 Hz.
+Sentences decline 5–6 dB from start to end as a matter of ordinary prosody. Look
+at one spectrum on its own and you will find "defects" in all of it, and the
+ones you find will be the speaker.
+
+So diagnosis is always **comparison**. The whole method is choosing the right
+thing to compare against.
+
+---
+
+## Compare against something inside the same file
+
+Ranked by how much they can tell you. Prefer the highest one available.
+
+### 1. The clean original, if it exists
+
+If the undamaged take is on disk, this is the whole job — measure both, subtract,
+and the difference _is_ the defect. Nothing below is as good. Look for it before
+anything else.
+
+### 2. The pauses
+
+The strongest reference that lives inside a single file. Speech stops; whatever
+is still there in the gap is not the voice.
+
+**What it answers: "was something added?"**
+
+Anything audible in the pauses is additive — hum, rumble, hiss, room tone. It was
+laid on top, so it can be subtracted, and this is a reliable positive finding.
+
+**What it does NOT answer: "was something filtered?"** — and getting this
+backwards is how the method produces a confident wrong answer.
+
+A filter multiplies. Applied to a file whose gaps already sit at the
+quantisation floor, it leaves them at the quantisation floor: near-silence times
+anything is still near-silence. So the pause carries no trace of it. Measured on
+one take with a −9 dB shelf above 2.5 kHz applied to the whole file:
+
+|                   | 1 kHz | 5 kHz | tilt      |
+| ----------------- | ----- | ----- | --------- |
+| pause, undamaged  | −91.0 | −91.0 | +0.0      |
+| pause, shelved    | −91.0 | −91.0 | **+0.0**  |
+| speech, undamaged | −34.7 | −42.8 | −8.1      |
+| speech, shelved   | −35.4 | −48.5 | **−13.1** |
+
+The defect is a clear 5 dB in the speech and **exactly zero** in the pause.
+
+So: **never use a null result from the pause spectrum to rule out EQ.** A run
+that did exactly that — measured the pause, found it smooth, and concluded
+"static EQ of any type or Q is ruled out" — went on to treat an inaudible
+−72 dBFS rumble as the defect and shipped a high-pass for a file whose actual
+problem was that it had no top end.
+
+The pause spectrum _is_ a transfer function only when the gaps carry a real
+recorded noise floor that passed through the same filter. A room-tone bed does;
+a digitally clean take does not. Check which you have before trusting it: if the
+gaps are within a few dB of the quantisation floor, this reference can find
+additive content and nothing else.
+
+### 3. The speech's own tilt, for a suspected filter
+
+When the pause cannot see a filter (above), the only thing left carrying it is
+the speech. Read the tilt across a few 1/3-octave bands rather than any single
+one — `1k / 3.2k / 5k / 7k` is enough to see a shelf:
+
+```bash
+for f in 1000 3200 5000 7000; do third voice.wav $f; done
+```
+
+Speech falls away steadily above about 1 kHz, so a downward slope is expected;
+what you are looking for is a slope that keeps steepening, or a step. In the
+table above, −8.1 dB from 1 k to 5 k is an ordinary voice and −13.1 dB is the
+same voice with 9 dB taken off the top.
+
+**This is a candidate, not a verdict.** Where the ordinary slope ends and a
+defect begins is speaker-dependent, and you have no baseline for this speaker.
+Say what you measured and what it would mean, and let somebody hear it.
+
+### 4. The file against itself over time
+
+For anything level-related, compare each passage to the track's own median rather
+than to a target. That is what `levellingResult` does, and it is why an already
+even track comes back untouched.
+
+---
+
+## Do not compare against a different voice
+
+Both wrong answers in the evaluation that produced this page came from an
+external reference, and both were argued rigorously from bad ground:
+
+- **A published average spectrum** (LTASS and friends). One run concluded
+  "+10 dB above 7 kHz, split-half stable, gating-independent" on a file whose
+  actual defect was +6.6 dB at 200 Hz. Its supporting claim — 10 kHz sitting
+  6.2 dB above 6.3 kHz — measured 0.6 dB on re-check, and measured the same in
+  the clean original. Published curves are mixed-sex, mixed-corpus, and
+  mixed-microphone; the gap between them and any one speaker is larger than most
+  defects.
+- **A synthesised control voice** (`say`, a TTS take, another narrator). One run
+  generated a control this way, found the spectrum "normal", and missed a −6.9 dB
+  shelf. Two speakers differ by more than 7 dB across the top octaves as a matter
+  of course, so a cross-voice comparison cannot resolve a defect that size.
+
+If neither the original nor usable pauses exist — continuous speech, or gaps that
+are digital silence and so carry no channel — then a static tonal defect is
+**genuinely under-determined**.
+
+Report that. It is a finding, not a failure to find one, and it is the correct
+answer rather than the fallback when the better methods are unavailable. Give
+the author the two or three readings that fit and ask which they hear; they can
+listen, and that one sentence from them collapses the whole problem.
+
+**This is the point where a capable agent goes wrong.** Told a thing is
+under-determined, the instinct is to invent a cleverer measurement and escape
+it — and something will always be found, because a single voice's spectrum is
+full of peaks and valleys that survive any amount of statistical rigour. An
+elaborate novel method reaching a confident conclusion, on a file where the two
+reliable references were both unavailable, is the _signature_ of this failure,
+not evidence against it. If you notice yourself building one, stop and report
+the ambiguity instead.
+
+---
+
+## Recipes
+
+All verified with ffmpeg 8.1.1. `-hide_banner` keeps the output readable;
+`volumedetect` prints to stderr, so do not silence it with `-v error`.
+
+### Band energy, in proportional bands
+
+**Use proportional bandwidths or the numbers lie.** A fixed 2000 Hz-wide band at
+10 kHz collects more energy than a 1200 Hz-wide band at 6.3 kHz for no reason but
+its width, which manufactures a high-frequency excess that is not there. One
+third of an octave is `f × 0.2316`.
+
+```bash
+third() {
+  w=$(python3 -c "print(round($2*0.2316))")
+  ffmpeg -hide_banner -i "$1" -af "bandpass=f=$2:width_type=h:w=$w,volumedetect" \
+    -f null - 2>&1 | grep -m1 mean_volume
+}
+third voice.wav 200     # weight / boom
+third voice.wav 3200    # presence / harshness
+```
+
+Read them as a shape across 100 / 200 / 400 / 1k / 3.2k / 7k, and read the shape
+against a reference from the list above — never on its own.
+
+### The noise floor, and what is in it
+
+```bash
+ffmpeg -hide_banner -i voice.wav -af astats=metadata=1 -f null - 2>&1 | grep -i 'noise floor'
+```
+
+`-inf` means digital silence in the gaps: no additive noise, so rumble, hiss and
+room tone are all ruled out in one command. A real number is the level of
+whatever is sitting under the voice. To see its _shape_, cut a pause out with
+`-ss`/`-t` and run the band recipe on that slice alone.
+
+### Level over time
+
+```bash
+ffmpeg -hide_banner -i voice.wav -af ebur128=framelog=quiet -f null - 2>&1 | tail -6
+```
+
+LRA under ~3 LU is even. Then window it, because LRA hides a single sagging
+passage:
+
+```bash
+for s in 0 1.2 2.4 3.6 4.8 6.0; do
+  ffmpeg -hide_banner -ss $s -t 1.2 -i voice.wav -af volumedetect -f null - 2>&1 |
+    grep -m1 mean_volume
+done
+```
+
+**A 4–6 dB spread across windows is normal speech**, not a defect — sentences
+decline as they end. Injected unevenness looks like 12 dB or more. Levelling a
+track that only has declination flattens the prosody and is heard as robotic.
+
+### Pitch, before blaming the low end
+
+```bash
+ffmpeg -hide_banner -i voice.wav -af "lowpass=f=400,astats=metadata=1" -f null - 2>&1 | grep -i 'peak level'
+```
+
+A voice has no energy below its own fundamental, so a "missing" 100 Hz on a
+speaker whose F0 is 210 Hz is the speaker, not a rolloff.
+
+The same fact runs the other way, and that direction is the trap: **a boost near
+the fundamental is indistinguishable from that voice being naturally chesty.**
+Both look like energy at F0, because both are.
+
+So the rule is symmetric, and the dangerous half is the second one:
+
+- Do not call a peak at F0 a defect on its own evidence.
+- **Do not dismiss one either.** "The peak is at 200 Hz, F0 is 185 Hz, therefore
+  it is the fundamental" is not a diagnosis — it is the same observation
+  restated, and it discards the one candidate most likely to be real. Boominess
+  _is_ excess energy at the bottom of a voice; that is what the word means.
+
+What you can do is measure how much, against the same file's midrange:
+
+```bash
+third voice.wav 200      # or the nearest 1/3-octave band to F0
+third voice.wav 1000
+```
+
+In an ordinary take these land within a couple of dB of each other. A low band
+sitting **more than about 4 dB above the 1 kHz band** is a strong boom or mud
+candidate. Measured across one voice damaged several ways: undamaged +0.9,
+harsh +0.6, dull +2.0; boomy +6.7, muddy +5.8. Treat the figure as indicative
+rather than a threshold — it is one speaker — but the separation is wide, and a
+reading up at +6 is worth raising even when you cannot explain it.
+
+It still cannot tell you whether a filter did that or the speaker did, so report
+it as a candidate. That is the whole answer here: measure it, name it, hand the
+choice to somebody who can hear it.
+
+---
+
+## Then, and only then, the symptom table
+
+Measurement gives you the band and the kind. `SKILL.md`'s table and
+`presets.md`'s fuller one turn that into a fix. Going the other way round —
+picking a plausible fix and finding evidence for it — is how both wrong answers
+in the evaluation happened, and both were long, careful and confident.
+
+One habit that catches it: before applying anything, state what you would expect
+to measure **if you are wrong**, and check that too.