Initial commit: Tonemark PWA

Tonemark is a SvelteKit PWA for transcribing YouTube videos, audio
and video files, and microphone recordings using a local Whisper backend.

Features:
- Dark glassmorphic UI with electric-lime accent (5 switchable themes)
- Rail nav (desktop) / tab bar (mobile) layout
- Drop zone, YouTube URL input, and live audio recording inputs
- Audio mode waveform cards (none / standard / aggressive / auto)
- Real-time transcription progress with animated waveform
- Job queue with SSE streaming updates
- Push notifications on job completion
- PWA with native SvelteKit service worker
- SRT / TXT / MD / JSON transcript downloads

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Dockerfile

@@ -0,0 +1,41 @@
+# syntax=docker/dockerfile:1
+
+# ── Stage 1: build ──────────────────────────────────────────────────────────
+FROM node:22-alpine AS builder
+
+WORKDIR /app
+
+# Install dependencies first (better layer caching)
+COPY package.json package-lock.json ./
+RUN npm ci
+
+# Copy source and build
+COPY . .
+RUN npm run build
+
+# Prune dev dependencies
+RUN npm prune --production
+
+# ── Stage 2: runtime ─────────────────────────────────────────────────────────
+FROM node:22-alpine AS runtime
+
+WORKDIR /app
+
+# Non-root user for security
+RUN addgroup -g 1001 tonemark && \
+    adduser -D -u 1001 -G tonemark tonemark
+
+# Copy built output and production node_modules
+COPY --from=builder --chown=tonemark:tonemark /app/build ./build
+COPY --from=builder --chown=tonemark:tonemark /app/node_modules ./node_modules
+COPY --from=builder --chown=tonemark:tonemark /app/package.json ./
+
+USER tonemark
+
+EXPOSE 3000
+
+ENV NODE_ENV=production \
+    PORT=3000 \
+    HOST=0.0.0.0
+
+CMD ["node", "build/index.js"]