chore: consolidate to single ruff config in root pyproject.toml

- Merge web ruff settings (select E/F/I/UP, line-length 100) into root config
- Remove [tool.ruff] section from web/pyproject.toml
- Remove "web" from root ruff exclude list
- Simplify pre-commit hook to one command: ruff check .
- Update CI to use: uv run ruff check . (from repo root)

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

.gitlab/.gitlab-ci.yml

@@ -45,7 +45,7 @@ test:web:
   script:
     - uv sync --all-packages
     - cd web && uv run pytest tests/ -x -q
-    - cd web && uv run ruff check src/ tests/
+    - uv run ruff check .
 
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