Docs reorg, config refactor, and ItemValues index fix

- Moved all documentation to docs/ and updated README with categorized links and new docs/INDEX.md
- Added HOW_TO_SWITCH_DATABASE.md and several new analysis/action docs
- Introduced db-config.ps1 for centralized DB config; all scripts now use it for easy DB switching
- Added db-quick.ps1 for interactive diagnostics and index management
- Updated Add-All-Indexes.bat to use db-config.ps1
- Added Fix-ItemValues-Performance.ps1 to create 3 critical indexes on ItemValues, addressing 1.3B row seq scan issue
- Updated performance_indexes.sql with new ItemValues indexes and ANALYZE
- Updated diagnostics.sql and database_report.txt for improved output and clarity
- All scripts and docs now reference the new config and index optimization workflow

sql/diagnostics.sql

@@ -355,7 +355,7 @@ BEGIN
         RAISE NOTICE 'RECOMMENDATION: Run VACUUM ANALYZE or adjust autovacuum settings';
     END IF;
     
-    RAISE NOTICE 'Diagnostic report complete.';
+    -- RAISE NOTICE 'Diagnostic report complete.';
 END $$;
 
 \echo ''

sql/performance_indexes.sql

@@ -118,6 +118,28 @@ ON library."PeopleBaseItemMap" (ItemId, PeopleId);
 CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_itemvalues_map_value 
 ON library."ItemValuesMap" (ItemValueId, ItemId);
 
+-- ============================================================================
+-- ItemValues Table Indexes (Critical Performance Optimization)
+-- ============================================================================
+
+\echo 'Creating indexes on ItemValues table...'
+
+-- Index for CleanValue lookups (genre/tag searches by name)
+-- Fixes: 1.3 billion row sequential scans
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_itemvalues_cleanvalue 
+ON library."ItemValues" ("CleanValue") 
+WHERE "CleanValue" IS NOT NULL;
+
+-- Index for Value lookups (direct value searches)
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_itemvalues_value 
+ON library."ItemValues" ("Value") 
+WHERE "Value" IS NOT NULL;
+
+-- Index for ItemValueId + CleanValue (ItemValuesMap joins)
+-- Improves genre/tag filtering performance
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_itemvalues_id_cleanvalue 
+ON library."ItemValues" ("ItemValueId", "CleanValue");
+
 -- ============================================================================
 -- ActivityLog Table Indexes
 -- ============================================================================
@@ -159,6 +181,7 @@ ANALYZE library."BaseItemProviders";
 ANALYZE library."UserData";
 ANALYZE library."PeopleBaseItemMap";
 ANALYZE library."ItemValuesMap";
+ANALYZE library."ItemValues";
 ANALYZE library."MediaStreamInfos";
 
 -- Analyze ActivityLog if it exists