Initial commit: RehearsalHub POC

Full-stack self-hosted band rehearsal platform:

Backend (FastAPI + SQLAlchemy 2.0 async):
- Auth with JWT (register, login, /me, settings)
- Band management with Nextcloud folder integration
- Song management with audio version tracking
- Nextcloud scan to auto-import audio files
- Band membership with link-based invite system
- Song comments
- Audio analysis worker (BPM, key, loudness, waveform)
- Nextcloud activity watcher for auto-import
- WebSocket support for real-time annotation updates
- Alembic migrations (0001–0003)
- Repository pattern, Ruff + mypy configured

Frontend (React 18 + Vite + TypeScript strict):
- Login/register page with post-login redirect
- Home page with band list and creation form
- Band page with member panel, invite link, song list, NC scan
- Song page with waveform player, annotations, comment thread
- Settings page for per-user Nextcloud credentials
- Invite acceptance page (/invite/:token)
- ESLint v9 flat config + TypeScript strict mode

Infrastructure:
- Docker Compose: PostgreSQL, Redis, API, worker, watcher, nginx
- nginx reverse proxy for static files + /api/ proxy
- make check runs all linters before docker compose build

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

worker/Dockerfile

@@ -0,0 +1,30 @@
+# Stage 1: Essentia builder
+# Essentia doesn't have wheels for Python 3.12 yet; we use the official image
+# and copy the bindings into our final stage via a bind mount.
+FROM mtgupf/essentia:latest AS essentia-builder
+
+FROM python:3.12-slim AS base
+WORKDIR /app
+
+# System dependencies for audio processing
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ffmpeg \
+    libsndfile1 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy Essentia Python bindings from builder (best-effort: no-op if the library
+# wasn't built for this Python version or the path doesn't exist).
+# COPY does not support shell redirections, so we use RUN --mount instead.
+RUN --mount=type=bind,from=essentia-builder,source=/usr/local/lib,target=/essentia_lib \
+    find /essentia_lib -maxdepth 4 -name "essentia*" \
+        -exec cp -r {} /usr/local/lib/python3.12/site-packages/ \; \
+    2>/dev/null || true
+
+RUN pip install uv
+
+FROM base AS production
+COPY pyproject.toml .
+RUN uv sync --no-dev --frozen || uv sync --no-dev
+COPY . .
+ENV PYTHONPATH=/app/src
+CMD ["uv", "run", "python", "-m", "worker.main"]