Fix standalone database "restarting" status flickering and add restart tracking

- Fix status flickering: Track databases in active/transient states (restarting, starting, created, paused) not just running
- Add isActiveOrTransient() helper to distinguish between active states and terminal states (exited, dead)
- Add safeguard: Protect updateNotFoundDatabaseStatus() from marking as exited when containers collection is empty
- Add restart_count tracking: New migration adds restart_count, last_restart_at, last_restart_type to all standalone database tables
- Update 8 database models with $casts for new restart tracking fields
- Update GetContainersStatus to extract RestartCount from Docker and update database models
- Reset restart tracking when database exits completely

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

app/Models/StandalonePostgresql.php

@@ -19,6 +19,8 @@ class StandalonePostgresql extends BaseModel
     protected $casts = [
         'init_scripts' => 'array',
         'postgres_password' => 'encrypted',
+        'restart_count' => 'integer',
+        'last_restart_at' => 'datetime',
     ];
 
     protected static function booted()