v0.1.6 — Phase 6 automatic scans

Phase 6 delays the first scan until Home Assistant has fully started, then enables the configured periodic interval. Manual and scheduled refreshes are serialized, unchanged missing-entity results do not rewrite the persistent notification, and dashboard loading failures are exposed through sensor and downloadable diagnostics. The sensor now reports scan_interval_minutes. Options retain previously saved values. Includes explicit ConfigEntry wiring for Home Assistant 2026.8 compatibility and 26 passing tests.