Add synchronized Dashboard time-range interaction

[BorisTyshkevich]

What & why

Closes #334.

Adds authoritative zero-or-one saved-query time-range metadata, conservative authoring-time inference, and on-demand Dashboard group derivation. Compatible temporal charts now share exact-timestamp crosshairs and support plain-mouse range brushing; both filters are validated and committed atomically through the existing typed execution pipeline, with stale-wave protection and full route/chart cleanup.

The implementation preserves explicit opt-out, independent groups, non-chart execution membership, manual keyboard-accessible filter editing, modifier-based tile movement, and the single-file/no-new-runtime-dependency architecture.

Verification

• npm test — 167 files / 5,064 tests; 100% statements and lines
• npm run build — dist/sql.html built successfully
• npx playwright test tests/e2e/time-range.spec.js — 30 passed across Chromium, Firefox, and WebKit
• git diff --check

Checklist

• npm test passes (including per-file coverage)
• Tests added/updated with the code
• npm run build succeeds
• Layers kept honest
• No new runtime dependency
• CHANGELOG updated
• Affected tracked work reconciled