feat(ui): add Catppuccin themes

[mfkd]

Summary

• Add built-in Catppuccin Latte and Mocha themes.
• Wire the new theme ids through app and OpenTUI theme resolution.
• Update docs, changelog, and theme coverage tests.

Closes #304.

Testing

• bun run typecheck
• bun test

[greptile-apps]

Greptile Summary

This PR adds Catppuccin Latte (light) and Catppuccin Mocha (dark) as two new built-in themes, wiring them through the AppTheme array, the HUNK_DIFF_THEME_NAMES public constant, the OpenTUI component type, and the UI menu — with docs and tests updated throughout.

• src/ui/themes.ts: Adds the full official Catppuccin palette as CATPPUCCIN_PALETTES, a createCatppuccinTheme factory that maps palette tokens to Hunk's semantic slots via blendHex, and registers both themes in the THEMES array.
• src/opentui/themes.ts: Extends HUNK_DIFF_THEME_NAMES so external consumers see the new identifiers in the public type.
• src/ui/themes.test.ts (new): Dedicated suite verifying sentinel palette values, derived diff background math, semantic color distinctness, and syntax-role mapping.

Confidence Score: 4/5

Safe to merge — the theme additions are self-contained, all changed files have tests, and the palette values match the official Catppuccin spec.

The two style concerns are non-blocking: catppuccinBlend is a harmless passthrough, and createCatppuccinTheme's free appearance parameter could produce a mismatched theme if a future caller pairs the wrong flavor with the wrong appearance, but the two existing call sites are correct. No logic errors, missing cases, or broken contracts were found.

src/ui/themes.ts — the createCatppuccinTheme signature accepts appearance independently of flavor, which is worth tightening before more Catppuccin flavors (Frappe, Macchiato) are added.

Important Files Changed

Filename	Overview
src/ui/themes.ts	Adds CATPPUCCIN_PALETTES, createCatppuccinTheme, and two new theme entries; palette values match the official spec and the blending logic is correct, though the catppuccinBlend wrapper and the freely-passable appearance parameter are minor design rough spots.
src/opentui/themes.ts	Extends HUNK_DIFF_THEME_NAMES constant and HunkDiffThemeName union to include the two new Catppuccin variants; straightforward and consistent with existing pattern.
src/ui/themes.test.ts	New dedicated test file verifying palette sentinel values, derived diff background correctness, semantic distinctness, and syntax-role mapping; thorough coverage of the new themes.
src/ui/diff/pierre.test.ts	Correctly adds Catppuccin Latte and Mocha to the markdown-remap test and only Mocha to the dark-theme isolation test; omission of Latte is intentional and matches the pre-existing pattern for Paper.
src/opentui/HunkDiffView.test.tsx	Updates snapshot assertion for HUNK_DIFF_THEME_NAMES to include the two new identifiers; correct and complete.
src/ui/lib/ui-lib.test.ts	Extends theme-menu label assertion and adds syntaxStyle existence checks for both Catppuccin variants; no issues.
docs/opentui-component.md	Updates the theme prop type column to include the two new identifiers; accurate and complete.
README.md	Adds catppuccin-latte and catppuccin-mocha to the inline comment listing valid theme values; accurate.
CHANGELOG.md	Single entry documenting the two new themes under Added; correct placement.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["CATPPUCCIN_PALETTES\n(latte | mocha)"] --> B["createCatppuccinTheme(flavor, appearance)"]
    B --> C["catppuccinBlend / blendHex\n(diff backgrounds, accents, notes)"]
    B --> D["withLazySyntaxStyle\n(lazy SyntaxStyle init)"]
    D --> E["THEMES array\n[...existing, latte, mocha]"]
    E --> F["resolveTheme(id, themeMode)"]
    F --> G["AppTheme\n(id, label, appearance, colors…)"]

    H["HUNK_DIFF_THEME_NAMES\n(opentui/themes.ts)"] --> I["HunkDiffThemeName union type"]
    I --> J["HunkDiffView theme prop"]

    G --> K["UI rendering\n(diff rows, syntax, badges)"]
    J --> K

Loading

Prompt To Fix All With AI

Fix the following 2 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 2
src/ui/themes.ts:189-192
The `appearance` value for each Catppuccin flavor is fixed by definition — Latte is always `"light"` and Mocha is always `"dark"`. Accepting it as a free parameter means a caller could pass `createCatppuccinTheme("latte", "dark")`, producing a visually light theme whose `appearance` field says `"dark"`. The `resolveTheme` function and any rendering pipeline that branches on `appearance` would then apply dark-mode transforms to a light palette. Deriving `appearance` from `flavor` inside the function removes this class of misuse entirely.

```suggestion
/** Map official Catppuccin palette tokens into Hunk's semantic theme slots. */
function createCatppuccinTheme(flavor: CatppuccinFlavor) {
  const palette = CATPPUCCIN_PALETTES[flavor];
  const label = flavor === "latte" ? "Catppuccin Latte" : "Catppuccin Mocha";
  const appearance: AppTheme["appearance"] = flavor === "latte" ? "light" : "dark";
```

### Issue 2 of 2
src/ui/themes.ts:184-188
`catppuccinBlend` is a one-line passthrough that delegates directly to the already-imported `blendHex` without adding any logic or guards. The call sites already read clearly with `blendHex`, so this wrapper adds indirection without benefit.

```suggestion
/** Map official Catppuccin palette tokens into Hunk's semantic theme slots. */
```

_{Reviews (1): Last reviewed commit: "feat(ui): add Catppuccin themes" | Re-trigger Greptile}