feat: add DevOptimizeDB flag to control SQLite optimization

Added a new DevOptimizeDB configuration flag (default true) that controls
whether SQLite PRAGMA OPTIMIZE and ANALYZE commands are executed. This allows
disabling database optimization operations for debugging or testing purposes.

The flag guards optimization commands in:
- db/db.go: Initial connection, post-migration, and shutdown optimization
- persistence/library_repository.go: Post-scan optimization
- db/migrations/migration.go: ANALYZE during forced full rescans

Set ND_DEVOPTIMIZEDB=false to disable all database optimization commands.

persistence/library_repository.go

@@ -179,7 +179,9 @@ func (r *libraryRepository) ScanEnd(id int) error {
 	// https://www.sqlite.org/pragma.html#pragma_optimize
 	// Use mask 0x10000 to check table sizes without running ANALYZE
 	// Running ANALYZE can cause query planner issues with expression-based collation indexes
-	_, err = r.executeSQL(Expr("PRAGMA optimize=0x10000;"))
+	if conf.Server.DevOptimizeDB {
+		_, err = r.executeSQL(Expr("PRAGMA optimize=0x10000;"))
+	}
 	return err
 }