Include viz extras in MCP container image

Adds --extra viz to uv sync so matplotlib and plotly are available
for visualize_tides and visualize_conditions in production.

Dockerfile.mcp

@@ -6,7 +6,7 @@ COPY pyproject.toml uv.lock README.md ./
 COPY src/ src/
 
 RUN --mount=type=cache,target=/root/.cache/uv \
-    uv sync --frozen --no-dev --no-editable
+    uv sync --frozen --no-dev --no-editable --extra viz
 
 # --- Runtime ---
 FROM python:3.12-slim-bookworm AS runtime