Fix numeric sorting in dashboard standings

[bensynapse]

I maintain Live Tennis API.

Fixes #1294.

The API returns points as decimal strings, and both existing comparisons sorted them as text, placing 9 above 12. Use one numeric comparison for the Points/Elo columns, preserve the order of equal scores, and sort a copy before applying the row limit. The Name header now compares team.name instead of a missing field on the standings input.

Validation:

• cd frontend && pnpm test passes (TypeScript and formatting).
• docker build --file frontend/Dockerfile frontend passes. The build emits Vite configuration/plugin and bundle-size warnings.
• 25 browser checks pass against the actual dashboard in both the Vite development server and the Docker client, using mocked tournament/stage API responses. They cover descending/ascending points, negative and decimal values, equal scores, both Swiss Elo headers, team names, the 100-row limit, and empty standings. The same checks produced 17 sorting failures before the fix. No browser page errors occurred.

To reproduce the reported case, load a round-robin stage with point totals 9, 12, 11, and 10: the initial order is now 12, 11, 10, 9, and clicking Points reverses it numerically. Backend/database integration was not exercised.