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>

api/src/rehearsalhub/repositories/base.py

@@ -0,0 +1,53 @@
+"""Generic async repository. All concrete repos extend BaseRepository[T]."""
+
+from __future__ import annotations
+
+import uuid
+from typing import Any, Generic, Sequence, TypeVar
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from rehearsalhub.db.models import Base
+
+ModelT = TypeVar("ModelT", bound=Base)
+
+
+class BaseRepository(Generic[ModelT]):
+    model: type[ModelT]
+
+    def __init__(self, session: AsyncSession) -> None:
+        self.session = session
+
+    async def get_by_id(self, id: uuid.UUID) -> ModelT | None:
+        return await self.session.get(self.model, id)
+
+    async def list(self, **filters: Any) -> Sequence[ModelT]:
+        stmt = select(self.model).filter_by(**filters)
+        result = await self.session.execute(stmt)
+        return result.scalars().all()
+
+    async def create(self, **kwargs: Any) -> ModelT:
+        obj = self.model(**kwargs)
+        self.session.add(obj)
+        await self.session.flush()
+        await self.session.refresh(obj)
+        return obj
+
+    async def update(self, obj: ModelT, **kwargs: Any) -> ModelT:
+        for key, value in kwargs.items():
+            setattr(obj, key, value)
+        await self.session.flush()
+        await self.session.refresh(obj)
+        return obj
+
+    async def delete(self, obj: ModelT) -> None:
+        await self.session.delete(obj)
+        await self.session.flush()
+
+    async def count(self, **filters: Any) -> int:
+        from sqlalchemy import func, select
+
+        stmt = select(func.count()).select_from(self.model).filter_by(**filters)
+        result = await self.session.execute(stmt)
+        return result.scalar_one()