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>

scripts/hooks/pre-commit

@@ -11,12 +11,8 @@ if [[ ! -x "$RUFF" ]]; then
     exit 1
 fi
 
-echo "→ ruff check (root)"
+echo "→ ruff check"
 "$RUFF" check --fix "$REPO_ROOT"
 
-echo "→ ruff check (web/src web/tests)"
-"$RUFF" check --fix "$REPO_ROOT/web/src" "$REPO_ROOT/web/tests" \
-    --config "$REPO_ROOT/web/pyproject.toml"
-
 # Re-stage any files ruff fixed so they land in the commit.
 git diff --name-only | xargs -r git add