feat: add Remotion project scaffolding and subtitle tools

Remotion project:
- package.json with Remotion 4.0.522, React 19, Tailwind v4
- tsconfig.json (strict, ES2018, Bundler module resolution)
- remotion.config.ts (rspack, jpeg image format)
- ESLint flat config, Prettier config
- Root component and MyComposition placeholder (1280x720, 30fps, 60 frames)

Subtitle tools:
- src/lrc2srt.ts — LRC to SRT converter (minimal, no dependencies)
- ffmpeg.sh — helper for baking ASS subtitles or static-image+audio bypass

.gitignore

@@ -1,4 +1,4 @@
-# --- Binary input assets (per README guideline) ---
+# Binary input assets (per README guideline)
 # Audio
 *.mp3
 *.wav
@@ -31,22 +31,8 @@
 *.mkv
 *.webm
 
-# --- Video output ---
-*.mp4
-*.mov
-*.avi
-*.mkv
-*.webm
-
-# --- Remotion / Node.js ---
-node_modules/
-out/
-dist/
-remotion-studio/
-
-# --- OS / IDE ---
-.DS_Store
-Thumbs.db
-*.swp
-*.swo
-*~
+# Video output (Remotion out/ + any rendered videos)
+node_modules
+dist
+out
+.env