fix(panel): stop blank panel on HA 2026.8 (history preload crash)

[buggedcom]

Symptom

On HA 2026.8, the Data Points panel renders blank. Console shows:

partial-panel-resolver.ts:231 Uncaught (in promise) TypeError:
  Cannot read properties of undefined (reading 'external')
  ← preloadHistoryRouteComponents (bundle)
  ← ensureHaComponents → _ensureUiComponentsReady → connectedCallback

Cause

preloadHistoryRouteComponents (in src/lib/ha/ha-components.ts) force-loads the history route's components by creating a partial-panel-resolver, assigning it a { panels } stub hass, and calling _updateRoutes():

1. On HA 2026.8 _updateRoutes reads more hass fields and dereferences .external off one the stub doesn't have → TypeError.
2. _updateRoutes is now async, and it was called without await, so the rejection escaped the surrounding try/catch as an unhandled promise rejection. That derailed the panel's connectedCallback preload chain (_ensureUiComponentsReady only builds the shell on the success path), so the shell never built → blank panel.

Fix

• Pass the real home-assistant hass to the resolver instead of the { panels } stub. It's a superset of the old stub (still has .panels), so it's backward-compatible with older cores that only read panels, and it gives 2026.8 the field it dereferences.
• await _updateRoutes() so any failure is caught by the existing best-effort try/catch and the preload degrades gracefully (logs a warning, panel still renders) instead of blanking.

Both changes are strictly safer across HA versions: await undefined is a no-op on older synchronous _updateRoutes.

Verification

• pnpm lint (eslint + package-json + prettier + tsc) ✅
• pnpm exec vitest run …/ha-components.spec.ts ✅
• pnpm build rebuilt and committed (bundle banner → v0.6.2)

Note: I attempted a unit regression test but the shared ha-stubs.ts pre-registers the history pickers globally, which structurally prevents the preload path from running under vitest without brittle customElements mocking — left out rather than ship a flaky/timeout-prone test.

Bumps to 0.6.2.

🤖 Generated with Claude Code