Remove unsupported --no-editable flag from backend Dockerfile

backend/Dockerfile

@@ -37,13 +37,13 @@ ENV UV_COMPILE_BYTECODE=1
 # Install dependencies first (no source yet -- better caching)
 RUN --mount=type=cache,target=/root/.cache/uv \
     --mount=type=bind,source=pyproject.toml,target=pyproject.toml \
-    uv pip install --system --no-editable .
+    uv pip install --system .
 
 COPY src/ ./src/
 
 # Re-install with source to get the package registered
 RUN --mount=type=cache,target=/root/.cache/uv \
-    uv pip install --system --no-editable .
+    uv pip install --system .
 
 # Run as non-root
 RUN useradd --create-home --shell /bin/bash spicebook