feat(cli): add --lang and auto-infer phonemizer locale from voice prefix (#351)

* feat(cli): add --lang and auto-infer phonemizer locale from voice prefix

`hyperframes tts` was calling Kokoro's `model.create(text, voice=, speed=)`
with no language argument, so Kokoro's default phonemizer (en-us) was
applied regardless of the voice selected. Picking `ef_dora` or `jf_alpha`
and feeding it Spanish or Japanese text produced English-phonemized
output.

Closes #349.

- `manager.ts`: add `SUPPORTED_LANGS`, `inferLangFromVoiceId`, and
  `isSupportedLang`. Attach a `defaultLang` field to every bundled voice
  and expand the bundled list with `ef_dora`, `ff_siwis`, `jf_alpha`,
  `zf_xiaobei` so `--list` surfaces multilingual options.
- `synthesize.ts`: accept optional `lang: SupportedLang` in
  `SynthesizeOptions`, forward it to the Python worker as `argv[7]`.
  The worker introspects `Kokoro.create`'s signature and only passes
  `lang=` when the installed kokoro-onnx version supports it. Returned
  metadata now includes `lang` and `langApplied` so callers can detect
  silent no-ops. Bump the cached script filename to `synth-v2.py` so
  existing installs pick up the new script automatically.
- `commands/tts.ts`: add `--lang, -l` with validation against
  `SUPPORTED_LANGS`. Resolution order is explicit `--lang` > inferred
  from voice prefix > `en-us`. When explicit lang disagrees with the
  voice-implied lang (legitimate for stylized accents), emit a
  dim-level hint; suppress under `--json`. When kokoro-onnx silently
  ignores the kwarg, log that too. Update `--list` with a new
  "Lang code" column and add multilingual examples.
- Tests: new `manager.test.ts` covering every supported prefix, the
  unknown-prefix fallback, case-insensitivity, `isSupportedLang`
  validation, and a regression guard that every bundled voice has a
  valid `defaultLang` matching its ID.
- Docs: `docs/packages/cli.mdx` and `skills/hyperframes/references/tts.md`
  updated with the flag, examples, the espeak-ng dependency note for
  non-English phonemization, and the voice-prefix → lang table.

Backward compatibility:
- English voices (a*/b* prefixes) continue to phonemize as en-us / en-gb
  — no change.
- Non-English voices now phonemize correctly by default (bug fix, not a
  regression).
- Older kokoro-onnx versions that don't know the `lang` kwarg keep
  working via signature introspection; the CLI logs a dim note if
  `--lang` was requested but ignored.

Verification:
- `bun --cwd packages/cli test` — 128 tests pass (incl. 17 new).
- `bunx oxlint` and `bunx oxfmt --check` clean on changed files.
- `bun run build` succeeds.
- `npx tsx packages/cli/src/cli.ts tts --help` / `--list` render cleanly;
  invalid `--lang` produces a clean error with the valid-codes list.

* refactor(cli): simplify tts --lang implementation

Post-review cleanup on #351. Net -21 lines.

- Drop `defaultLang` field + `makeVoice()` helper from VoiceInfo —
  compute via `inferLangFromVoiceId(v.id)` at read time in listVoices.
  The only reader was the --list table; caching the derived value on
  every voice added a self-consistency invariant we had to test.
- Drop redundant `lang` field from SynthesizeResult — caller already
  knows the requested lang since it passed it in; only `langApplied`
  carries information the caller can't derive.
- Use `errorBox` for --lang validation to match the house style in
  render.ts (other validation errors already use errorBox).
- Reuse existing `langList` module constant in the validation error
  instead of re-joining SUPPORTED_LANGS.
- Inline `DEFAULT_LANG` — used once in inferLangFromVoiceId.
- Trim WHAT-restating comments and the duplicate prefix-enumeration
  JSDoc on inferLangFromVoiceId (VOICE_PREFIX_LANG already carries
  per-row comments).
- Clean up orphaned `synth*.py` files in ~/.cache/hyperframes/tts
  when writing the current versioned script, so repeated upgrades
  don't leak files.
- Drop the `EN-US` case-sensitive-rejection test assertion — the CLI
  lowercases input before validation, so accepting mixed case is a
  feature, not a bug.

Tests: 16/16 in `manager.test.ts`, 127/127 full CLI suite pass.
Lint + format + typecheck clean.

skills/hyperframes/references/tts.md

@@ -16,6 +16,25 @@ Match voice to content. Default is `af_heart`.
 
 Run `npx hyperframes tts --list` for all 54 voices (8 languages).
 
+## Multilingual Phonemization
+
+Kokoro voice IDs encode language in the first letter: `a`=American English, `b`=British English, `e`=Spanish, `f`=French, `h`=Hindi, `i`=Italian, `j`=Japanese, `p`=Brazilian Portuguese, `z`=Mandarin. The CLI auto-detects the phonemizer locale from that prefix — you don't need to pass `--lang` when the voice matches the text.
+
+```bash
+npx hyperframes tts "La reunión empieza a las nueve" --voice ef_dora --output es.wav
+npx hyperframes tts "今日はいい天気ですね" --voice jf_alpha --output ja.wav
+```
+
+Use `--lang` only to override auto-detection (e.g. stylized accents):
+
+```bash
+npx hyperframes tts "Hello there" --voice af_heart --lang fr-fr --output accented.wav
+```
+
+Valid `--lang` codes: `en-us`, `en-gb`, `es`, `fr-fr`, `hi`, `it`, `pt-br`, `ja`, `zh`.
+
+Non-English phonemization requires `espeak-ng` installed system-wide (`brew install espeak-ng` on macOS, `apt-get install espeak-ng` on Debian/Ubuntu).
+
 ## Speed Tuning
 
 - **0.7-0.8** — Tutorial, complex content