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>

packages/app/src/styles/unistyles.ts

@@ -6,6 +6,7 @@ import {
   darkMidnightTheme,
   darkClaudeTheme,
   darkGhosttyTheme,
+  darkPureBlackTheme,
 } from "./theme";
 
 StyleSheet.configure({
@@ -16,6 +17,7 @@ StyleSheet.configure({
     darkMidnight: darkMidnightTheme,
     darkClaude: darkClaudeTheme,
     darkGhostty: darkGhosttyTheme,
+    darkPureBlack: darkPureBlackTheme,
   },
   breakpoints: {
     xs: 0,
@@ -37,6 +39,7 @@ interface AppThemes {
   darkMidnight: typeof darkMidnightTheme;
   darkClaude: typeof darkClaudeTheme;
   darkGhostty: typeof darkGhosttyTheme;
+  darkPureBlack: typeof darkPureBlackTheme;
 }
 
 interface AppBreakpoints {