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/diagnostics.sql

@@ -265,13 +265,11 @@ BEGIN
             ORDER BY mean_exec_time DESC
             LIMIT 10
         LOOP
-            RAISE NOTICE 'Calls: %, Avg: %ms, Max: %ms, Total: %ms, %%: %, Query: %', 
+            RAISE NOTICE 'Calls: %, Avg: %ms, Max: %ms, Total: %ms, Percent: %%', 
                 query_rec.calls, 
                 query_rec.avg_time_ms, 
                 query_rec.max_time_ms, 
-                query_rec.total_time_ms, 
-                query_rec.percent_total, 
-                query_rec.query_preview;
+                query_rec.total_time_ms;
         END LOOP;
     END IF;
 END $$;
@@ -341,7 +339,7 @@ BEGIN
     FROM pg_stat_database WHERE datname = 'jellyfin';
     
     IF hit_ratio < 95 THEN
-        RAISE WARNING 'Low cache hit ratio: %%. Target: >95%%', hit_ratio;
+        RAISE WARNING 'Low cache hit ratio: %. Target: >95', hit_ratio;
         RAISE NOTICE 'RECOMMENDATION: Increase shared_buffers and effective_cache_size';
     END IF;