feat(app): add Pure black theme (#3012)

* feat(app): add AMOLED and all four Catppuccin themes

Add an AMOLED theme (pure black background) and the four official
Catppuccin flavors (Latte light, Frappé/Macchiato/Mocha dark) to the
appearance picker. Generalize the dark-theme builder to support a light
surface variant, register the new themes with Unistyles, and patch all
registered theme keys when applying font/syntax appearance settings.

* fix(app): localize Catppuccin + AMOLED theme labels across language packs

The initial theme commit pasted the English brand/flavor labels into every
locale. Localize them following each pack's convention: transliterate
Catppuccin and the coffee-flavor names into Arabic/Russian scripts, use
katakana/hanzi equivalents in ja/zh-CN, and standard loanwords in
fr/es/pt-BR. AMOLED is a universal acronym and stays as-is except where
the pack transliterates (Arabic).

* fix(app): make Latte terminal ANSI colors readable

* test(app): cover appearance theme picker options

* refactor(app): scope theme PR to AMOLED

* refactor(app): rename AMOLED theme to Pure Black

* fix(app): refine Pure black appearance

* test(app): wait for sidebar toggle icon

* test(app): remove hover timing race

---------

Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

docs/unistyles.md

@@ -345,7 +345,7 @@ Gotchas:
 - **Narrow the discriminated union before spreading.** `updateTheme`'s updater returns the theme union; spreading the union widens `colorScheme` to `"light" | "dark"`, which is assignable to neither concrete member. Branch on `t.colorScheme` so each branch spreads a single narrowed theme type (no `as`).
 - **`lineHeight.diff` is the code/diff line-height axis** — it is coupled to the code-font-size control (≈ `codeFontSize * 1.5`). Do NOT use it for prose. Markdown body line-height scales with the UI ramp (`Math.round(theme.fontSize.base * 1.4)`); routing prose through `lineHeight.diff` clips text at small code sizes.
 - **High-churn draft values** (live-while-typing in the appearance preview) bypass the theme: apply them as inline styles marked with `inlineUnistylesStyle` so per-keystroke values don't grow the `#unistyles-web` CSS registry.
-- **Mounted parsed content uses `AppearanceStyleBoundary`.** Markdown, syntax-highlighted code, and tool-call detail bodies can contain memoized/custom renderer trees that do not naturally re-run when runtime-patched appearance tokens change. Wrap the parsed surface once with `packages/app/src/components/appearance-style-boundary.tsx`; do not add local "appearance key" props at each callsite.
+- **The app shell uses one `AppearanceStyleBoundary`.** Runtime-patched numeric theme values are baked into Unistyles web classes rather than CSS variables, while parsed/memoized content also does not naturally re-run when appearance tokens change. The boundary sits below stable runtime providers in `app/_layout.tsx` and remounts the visual shell once. `applyAppearance` patches the active theme before inactive registry entries so its subscribers receive the committed values in the same update. Do not add local appearance keys or nested boundaries.
 - **Dynamic font tokens stay widened.** `fontFamily`, `fontSize`, and `lineHeight` on `commonTheme` are annotated `string`/`number` (not narrowed by `as const`) so the updater's return assigns; the platform default stacks live in `DEFAULT_UI_FONT_STACK` / `DEFAULT_MONO_FONT_STACK`.
 
 ## Debugging