chore(studio): remove fully rolled-out studio feature flags (#2889)

## What

Removes six Studio feature flags that have been default-`true` for 7+ weeks. Each is reachable under two env names, so this deletes **12 `VITE_STUDIO_*` env vars**:

| Flag constant | Env names removed | Default-on since |
|---|---|---|
| `STUDIO_PREVIEW_MANUAL_EDITING_ENABLED` | `VITE_STUDIO_ENABLE_PREVIEW_MANUAL_DRAGGING`, `VITE_STUDIO_PREVIEW_MANUAL_EDITING_ENABLED` | 2026-05-12 |
| `STUDIO_INSPECTOR_PANELS_ENABLED` (+ its `STUDIO_PREVIEW_SELECTION_ENABLED` alias) | `VITE_STUDIO_ENABLE_INSPECTOR_PANELS`, `VITE_STUDIO_INSPECTOR_PANELS_ENABLED` | 2026-05-12 |
| `STUDIO_BLOCKS_PANEL_ENABLED` | `VITE_STUDIO_ENABLE_BLOCKS_PANEL`, `VITE_STUDIO_BLOCKS_PANEL_ENABLED` | 2026-05-18 |
| `STUDIO_GSAP_PANEL_ENABLED` | `VITE_STUDIO_ENABLE_GSAP_PANEL`, `VITE_STUDIO_GSAP_PANEL_ENABLED` | 2026-05-28 |
| `STUDIO_KEYFRAMES_ENABLED` | `VITE_STUDIO_ENABLE_KEYFRAMES`, `VITE_STUDIO_KEYFRAMES_ENABLED` | 2026-06-05 |
| `STUDIO_RAZOR_TOOL_ENABLED` | `VITE_STUDIO_ENABLE_RAZOR_TOOL`, `VITE_STUDIO_RAZOR_TOOL_ENABLED` | 2026-06-10 |

## Why

Every one of these shipped as a rollout gate, went to `true`, and then stayed. Because none of them was ever flipped back, the `false` branch was unreachable in practice while still costing a real import, a real conditional, and a real "what happens if this is off?" question at ~90 call sites across 25 files.

The bigger cost is what the dead branch kept alive. Removing the flags also removes the disabled-Studio code paths that only existed to serve them:

- the greyed-out, `disabled`, "Manual editing is temporarily disabled" Inspector button in `StudioHeader` (and the `STUDIO_MANUAL_EDITING_DISABLED_TITLE` constant behind it)
- the inspector-off reset `useEffect` in `useDomSelection`, which force-cleared selection and redirected the right panel to Renders
- three selection kill-switch early-returns in `useDomSelection` (`applyDomSelection`, `handleTimelineElementSelect`, `applyMarqueeSelection`)
- the tab-redirect branch in `normalizeStudioUrlPanelTab`, whose `options.inspectorPanelsEnabled` parameter had no production caller at all (only tests passed it)

## How

No behavior change: every flag was removed by keeping its default-`true` side.

The call-site edits are three mechanical boolean shapes (`X && rest` → `rest`, `rest && X` → `rest`, `!X || rest` → `rest`), applied by script for uniformity. Everything else (ternaries, `if` guards, unreachable blocks, JSX wrappers that had no other condition) was done by hand and the whole diff was read line by line afterwards.

`resolveStudioBooleanEnvFlag` and the `import.meta.env` / `window.__HF_STUDIO_ENV__` plumbing stay: three flags still use them (`STUDIO_FLAT_INSPECTOR_ENABLED`, `STUDIO_SDK_CUTOVER_ENABLED`, `STUDIO_SDK_RESOLVER_SHADOW_ENABLED`). Its unit tests kept their coverage but now exercise a live flag pair instead of retired env names, so no dead `VITE_STUDIO_*` string is left in the repo.

Net **-191 lines** (236 insertions, 427 deletions across 25 files); most insertions are reindentation of JSX that lost a wrapper.

### Deliberately not in scope

Flags authored by other people are untouched, even where they look similarly settled:

- `VITE_STUDIO_ENABLE_FLAT_INSPECTOR` / `VITE_STUDIO_FLAT_INSPECTOR_ENABLED` (default true, but not mine)
- `VITE_STUDIO_SDK_CUTOVER_ENABLED`, `VITE_STUDIO_SDK_CUTOVER_FAMILIES`, `VITE_STUDIO_SDK_RESOLVER_SHADOW_ENABLED` (SDK cutover canary, still soaking)
- `VITE_HYPERFRAMES_NO_TELEMETRY`

Mine but genuinely long-lived configuration rather than rollout gates, so they stay: `VITE_STUDIO_DISCOVERY_PORTS`, `VITE_HYPERFRAMES_FEEDBACK_INTERVAL`, `VITE_HYPERFRAMES_NO_FEEDBACK` (a documented user opt-out), plus the `HYPERFRAMES_*` binary paths, API URLs, cache sizes, and timeouts.

`VITE_STUDIO_ENABLE_MOTION_PANEL` / `VITE_STUDIO_MOTION_PANEL_ENABLED` were already retired from production code before this PR; they only survived as placeholder names inside the resolver's unit tests, and this PR swaps those out.

## Test plan

- [x] Unit tests added/updated - dropped the two tests asserting removed flag defaults; retargeted the `resolveStudioBooleanEnvFlag` cases at a live flag pair; updated `studioUrlState` tests for the narrowed `normalizeStudioUrlPanelTab` signature (now also asserts an unknown tab returns `null`).
- [x] Manual testing performed - see below.
- [ ] Documentation updated (if applicable) - not needed; no removed name appears in `docs/`, `skills/`, or `registry/`. (`docs/changelog.mdx` has one historical entry naming `STUDIO_KEYFRAMES_ENABLED`; changelog history is left as written.)

```
packages/studio: bunx vitest run          # 280 files, 3116 tests pass, 1 skipped
packages/studio: bunx tsc --noEmit        # clean
bun run build                             # green (all packages)
bunx oxlint  <25 changed files>           # 0 warnings, 0 errors
bunx oxfmt --check <25 changed files>     # clean
```

Two extra checks, because part of this diff was script-generated:

1. Zero references to any removed flag constant or env name remain anywhere outside `docs/changelog.mdx`.
2. Diffed every string literal in each changed non-test file against `origin/main`. The only differences are the intended removals: the 12 env names, `"Manual editing is temporarily disabled"`, the `"cursor-not-allowed …"` disabled class, the 3-column `"1fr 1fr 1fr"` grid, and the `"renders"` redirect literals. No user-facing label, tooltip, or class string changed by accident.

packages/studio/src/player/components/Timeline.tsx

@@ -32,7 +32,6 @@ import {
   useTimelineTrackLayout,
 } from "./useTimelineTrackLayout";
 import { useTimelineKeyframeHandlers } from "./useTimelineKeyframeHandlers";
-import { STUDIO_KEYFRAMES_ENABLED } from "../../components/editor/manualEditingAvailability";
 import { useTrackGapMenu } from "./useTrackGapMenu";
 import { useTimelineGapHighlights } from "./useTimelineGapHighlights";
 import { useStudioPlaybackContextOptional } from "../../contexts/StudioContext";
@@ -126,7 +125,7 @@ export const Timeline = memo(function Timeline({
       ),
     [gsapAnimations],
   );
-  const labelMode = STUDIO_KEYFRAMES_ENABLED && hasKeyframedClips;
+  const labelMode = hasKeyframedClips;
   // Without the label column the pre-t=0 breathing room is still TRACKS_LEFT_PAD
   // (dropping it would jam clip 0 against the gutter on every non-keyframed
   // composition); in label mode the 232px label column already provides it.

packages/studio/src/player/components/TimelineLanes.tsx

@@ -17,7 +17,6 @@ import {
 } from "./timelineMultiDragPreview";
 import type { TimelineLaneBaseProps } from "./timelineLaneProps";
 import type { TimelineEditCallbacks } from "./timelineCallbacks";
-import { STUDIO_KEYFRAMES_ENABLED } from "../../components/editor/manualEditingAvailability";
 import { trackStudioKeyframeLaneExpand } from "../../telemetry/events";
 import { SPLIT_BOUNDARY_EPSILON_S } from "../../utils/timelineElementSplit";
 import { isAudioTimelineElement, isMusicTrack } from "../../utils/timelineInspector";
@@ -134,9 +133,12 @@ export function TimelineLanes({
           // The one keyframed element this track shows lanes for (selected, else
           // most lanes). A track can hold several elements; scoping to one keeps
           // their keyframes from cramming into a single row.
-          const keyframeClip = STUDIO_KEYFRAMES_ENABLED
-            ? resolveTrackKeyframeClip(els, laneCounts, selectedElementId, selectedElementIds)
-            : null;
+          const keyframeClip = resolveTrackKeyframeClip(
+            els,
+            laneCounts,
+            selectedElementId,
+            selectedElementIds,
+          );
           const keyframeClipKey = keyframeClip?.key ?? keyframeClip?.id;
           const keyframeClipExpanded =
             keyframeClipKey != null && expandedClipIds.has(keyframeClipKey);
@@ -249,8 +251,7 @@ export function TimelineLanes({
                     // Only the track's active keyframe clip shows expanded lanes;
                     // other clips (incl. siblings on a shared track) show compact
                     // diamonds on their own bar instead.
-                    const isTrackKeyframeClip =
-                      STUDIO_KEYFRAMES_ENABLED && elementKey === keyframeClipKey;
+                    const isTrackKeyframeClip = elementKey === keyframeClipKey;
                     const showsLanes = isTrackKeyframeClip && keyframeClipExpanded;
                     const capabilities = getTimelineEditCapabilities(el);
                     const isSelected =
@@ -428,35 +429,32 @@ export function TimelineLanes({
                           renderClipContent,
                           renderClipOverlay,
                         )}
-                        {STUDIO_KEYFRAMES_ENABLED &&
-                          !showsLanes &&
-                          keyframeCache?.get(elementKey) && (
-                            <TimelineClipDiamonds
-                              keyframesData={keyframeCache.get(elementKey)!}
-                              clipWidthPx={Math.max(previewElement.duration * pps, 4)}
-                              clipHeightPx={rowHeight - 2 * CLIP_Y}
-                              beatsActive={beatStripOnTrack}
-                              accentColor={clipStyle.accent}
-                              isSelected={isSelected}
-                              currentPercentage={
-                                previewElement.duration > 0
-                                  ? ((currentTime - previewElement.start) /
-                                      previewElement.duration) *
-                                    100
-                                  : 0
-                              }
-                              elementId={elementKey}
-                              selectedKeyframes={selectedKeyframes}
-                              onClickKeyframe={(_elId, target) =>
-                                onClickKeyframe?.(previewElement, target)
-                              }
-                              onShiftClickKeyframe={onShiftClickKeyframe}
-                              onContextMenuKeyframe={onContextMenuKeyframe}
-                              onMoveKeyframe={onMoveKeyframe}
-                              onSelectSegment={onSelectSegment}
-                              suppressClickRef={suppressClickRef}
-                            />
-                          )}
+                        {!showsLanes && keyframeCache?.get(elementKey) && (
+                          <TimelineClipDiamonds
+                            keyframesData={keyframeCache.get(elementKey)!}
+                            clipWidthPx={Math.max(previewElement.duration * pps, 4)}
+                            clipHeightPx={rowHeight - 2 * CLIP_Y}
+                            beatsActive={beatStripOnTrack}
+                            accentColor={clipStyle.accent}
+                            isSelected={isSelected}
+                            currentPercentage={
+                              previewElement.duration > 0
+                                ? ((currentTime - previewElement.start) / previewElement.duration) *
+                                  100
+                                : 0
+                            }
+                            elementId={elementKey}
+                            selectedKeyframes={selectedKeyframes}
+                            onClickKeyframe={(_elId, target) =>
+                              onClickKeyframe?.(previewElement, target)
+                            }
+                            onShiftClickKeyframe={onShiftClickKeyframe}
+                            onContextMenuKeyframe={onContextMenuKeyframe}
+                            onMoveKeyframe={onMoveKeyframe}
+                            onSelectSegment={onSelectSegment}
+                            suppressClickRef={suppressClickRef}
+                          />
+                        )}
                       </TimelineClip>
                     );
                     // Mounted for the track's keyframe clip in BOTH disclosure

packages/studio/src/player/components/useAutoExpandKeyframedClips.ts

@@ -1,7 +1,6 @@
 import { useEffect, useRef } from "react";
 import type { GsapAnimation } from "@hyperframes/core/gsap-parser";
 import { usePlayerStore } from "../store/playerStore";
-import { STUDIO_KEYFRAMES_ENABLED } from "../../components/editor/manualEditingAvailability";
 import { useStudioShellContextOptional } from "../../contexts/StudioContext";
 import { animationContributesLane } from "./TimelinePropertyLanes";
 
@@ -34,7 +33,6 @@ export function useAutoExpandKeyframedClips(gsapAnimations: Map<string, GsapAnim
   const projectId = useStudioShellContextOptional()?.projectId ?? null;
   const seen = useRef({ projectId, source: gsapAnimations, clips: new Set<string>() });
   useEffect(() => {
-    if (!STUDIO_KEYFRAMES_ENABLED) return;
     if (seen.current.projectId !== projectId) {
       const sourceChanged = seen.current.source !== gsapAnimations;
       seen.current = { projectId, source: gsapAnimations, clips: new Set() };

packages/studio/src/player/components/useTimelineTrackLayout.ts

@@ -2,7 +2,6 @@ import { useMemo, useRef } from "react";
 import type { GsapAnimation } from "@hyperframes/core/gsap-parser";
 import { animationLaneGroups } from "./TimelinePropertyLanes";
 import { usePlayerStore, type TimelineElement } from "../store/playerStore";
-import { STUDIO_KEYFRAMES_ENABLED } from "../../components/editor/manualEditingAvailability";
 import type { DraggedClipState } from "./timelineClipDragTypes";
 import { useTimelineTrackDerivations } from "./useTimelineTrackDerivations";
 import {
@@ -90,10 +89,7 @@ function useTimelineRowHeights(
     });
     return {
       laneCounts,
-      rowHeights: trackHeights(
-        heightTracks,
-        STUDIO_KEYFRAMES_ENABLED ? expandedClipIds : undefined,
-      ),
+      rowHeights: trackHeights(heightTracks, expandedClipIds),
     };
   }, [expandedClipIds, gsapAnimations, tracks, selectedElementId, selectedElementIds]);
   const rowHeightsRef = useRef<readonly number[]>(rowHeights);