Fix dev container startup for both API and web

API:
- Add python symlink (python3-slim has no bare 'python') so uv doesn't
  invalidate the baked venv on every container start
- Copy src/ before uv sync so hatchling installs rehearsalhub as a
  proper editable install (.pth pointing to /app/src) — previously
  sync ran with no source present, producing a broken empty wheel
- Remove ENV PYTHONPATH workaround (no longer needed with correct install)
- Add --reload-dir /app/src to scope uvicorn's file watcher to the
  mounted source directory

Web:
- Add COPY . . after npm install so index.html and vite.config.ts are
  baked into the image — without them Vite ignored port config and fell
  back to 5173 with no entry point

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

api/Dockerfile

@@ -3,11 +3,13 @@ WORKDIR /app
 RUN pip install uv
 
 FROM base AS development
-ENV PYTHONPATH=/app/src
+# python:3.12-slim has no bare 'python' binary; without this uv invalidates the baked venv on every start
+RUN ln -sf /usr/local/bin/python3 /usr/local/bin/python
 COPY pyproject.toml .
+COPY src/ src/
 RUN uv sync
 COPY . .
-CMD ["uv", "run", "uvicorn", "rehearsalhub.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]
+CMD ["uv", "run", "uvicorn", "rehearsalhub.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload", "--reload-dir", "/app/src"]
 
 FROM base AS lint
 COPY pyproject.toml .