🤖🤖🤖 Fix vertical scrolling in anomalies listing

[buggedcom]

Summary

Long anomalies listings were clipped by the panel shell, leaving monitors below the visible area unreachable. The listing now fills the available height and scrolls vertically.

 anomaly-monitors-panel :host
+  height: 100%;
+  overflow-y: auto;

• Add a GIVEN / WHEN / THEN regression spec and a Storybook interaction covering a long listing inside the real panel shell.
• Rebuild the frontend bundle.
• Update the series-row test to use Object.hasOwn(), resolving the ESLint failure that blocked CI tests.

Type of change

• Bug fix
• Tests

Evidence

• Before: Chrome DevTools measured a 1,796px listing inside a 928px container with hidden overflow. The browser regression failed because the listing exceeded the available height; the unit regression also failed.
• After: The listing fits the container, scrolls to its final monitor, and responds to Page Down. All 22 focused unit tests and 9 Storybook tests pass.

Testing

• Manually tested in Home Assistant using isolated Chrome DevTools and a temporary CSS override; the rebuilt bundle has not been deployed.
• New tests added to cover the change

Passed: focused Vitest unit and Storybook suites, pnpm build, pnpm sb:build, pnpm format, pnpm lint:types, and the full pnpm lint check. The series-row and Python-backed focused suites pass (71 tests) with CI’s PYTHON_BIN=python3 setting.

Merge Danger

Door: two-way — revert the CSS and rebuilt bundle.

Blast Radius: listing — sizing and vertical scrolling of the anomalies monitor panel.

Checklist

• Commit messages follow Conventional Commits
• Bundle rebuilt and committed
• No new TypeScript type errors