Complete multi-instance support: Phases 3–6 & deployment

- Implements Phases 3–6: session isolation, cache coordination, primary election, and file system monitor coordination for Jellyfin with PostgreSQL.
- Adds new database entities (Instance, DistributedLock, FileSystemChange) and EF model configurations.
- Includes SQL migration scripts and EF migration for all required tables, columns, and helper functions.
- Updates Device entity and JellyfinDbContext for multi-instance tracking.
- Integrates new DI services for instance registry, distributed locks, cache coordinator, and primary election.
- Adds publishing profiles (Win/Linux/FrameworkDependent) and automation script for deployment.
- Extensive documentation for architecture, setup, and publishing.
- All changes are backward compatible and build successfully.

sql/performance_indexes.sql

@@ -191,9 +191,9 @@ BEGIN
     IF EXISTS (
         SELECT 1 FROM information_schema.tables 
         WHERE table_schema = 'activitylog' 
-        AND table_name = 'ActivityLog'
+        AND table_name = 'ActivityLogs'
     ) THEN
-        ANALYZE activitylog."ActivityLog";
+        ANALYZE activitylog."ActivityLogs";
         RAISE NOTICE 'ActivityLog analyzed';
     END IF;
 END $$;