feat: modernize UI with Astro+Svelte and optimize Docker build

- Migrated frontend to Astro + Svelte 5 for cyberpunk aesthetic
- Switched to Bun for faster frontend builds
- Implemented multi-stage Docker build for smaller image size
- Refactored backend to serve static assets and proxy API requests
- Added recovery mode for manual file management

Dockerfile

@@ -1,18 +1,39 @@
+# --- Stage 1: Frontend Build (Bun) ---
+FROM oven/bun:1 as frontend
+WORKDIR /app/ui
+
+# Copy frontend code
+COPY ui/package.json ui/bun.lock ./
+RUN bun install --frozen-lockfile
+
+COPY ui .
+RUN bun run build
+
+# --- Stage 2: Backend (Python) ---
 FROM python:3.11-slim
 WORKDIR /app
 
-# 1. Install System Deps (ffmpeg) FIRST
-# These rarely change, so Docker will cache this layer forever.
+# 1. Install System Deps (ffmpeg, curl for yt-dlp)
 RUN apt-get update && apt-get install -y ffmpeg curl && rm -rf /var/lib/apt/lists/*
 RUN curl -L https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -o /usr/local/bin/yt-dlp && chmod a+rx /usr/local/bin/yt-dlp
 
-# 2. Install Python Deps SECOND
-# Only re-runs if requirements.txt changes
+# 2. Install Python Deps
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# 3. Copy Code LAST
-# Now, if you change code, only this fast step re-runs.
-COPY . .
+# 3. Copy Backend Code
+COPY ta_symlink.py .
+# Copy other backend files if any (templates/ was old, but maybe still needed if I missed something? No, I replaced routes.)
+# But just in case, I'll exclude templates from copy or just copy everything and ignore.
+# Using .dockerignore would be good, but explicit copy is fine too.
+# Let's copy specific files or everything. The previous dockerfile did `COPY . .`.
+# I should probably just copy the python file and any others.
+# Let's stick to what was there but ensure we copy the BUILT frontend.
 
+# 4. Copy Built Frontend from Stage 1
+# Python app expects: os.path.join(os.getcwd(), 'ui', 'dist')
+# defaults WORKDIR /app, so /app/ui/dist
+COPY --from=frontend /app/ui/dist ./ui/dist
+
+# 5. CMD
 CMD ["python", "ta_symlink.py"]