Add library_type_name column to media_items with auto-population trigger

- Add library_type_name VARCHAR(50) column to media_items table in schema.sql
- Create PostgreSQL trigger 'set_library_type_name_on_insert' that automatically
  populates library_type_name by joining libraries table with library_types on insert
- Add library_type_name parameter to CreateMediaItem SQL query
- Update Go models (models.go) to include LibraryTypeName field
- Add UpdateMediaItemChapterMetadata query method to querier.go
- Regenerate queries.sql.go with sqlc

This allows media items to store their library type (e.g., 'Books', 'Comics', 'Manga')
at the database level, enabling filtering and display without needing additional joins.

database/schema/schema.sql

@@ -180,7 +180,9 @@ CREATE TABLE IF NOT EXISTS media_items (
         --   "detected_at": "2024-01-15T10:30:00Z",
         --   "detection_method": "epub-toc" | "pdf-outline" | "page-breaks"
         -- }
-    chapter_metadata JSONB
+    chapter_metadata JSONB,
+    -- Need library_type_name for checks
+    library_type_name VARCHAR(50)
 );
 
 -- Add GIN indexes for fast array searches
@@ -195,6 +197,26 @@ ALTER TABLE media_items ADD COLUMN IF NOT EXISTS contributors_search TEXT[];
 CREATE INDEX IF NOT EXISTS idx_media_items_tags_search ON media_items USING GIN (tags_search);
 CREATE INDEX IF NOT EXISTS idx_media_items_contributors_search ON media_items USING GIN (contributors_search);
 
+-- Drop existing trigger if exists
+DROP TRIGGER IF EXISTS set_library_type_name_on_insert ON media_items;
+-- Drop existing function if exists
+DROP FUNCTION IF EXISTS set_library_type_name();
+
+-- Add trigger to populate library_type_name on insert
+CREATE OR REPLACE FUNCTION set_library_type_name() RETURNS TRIGGER AS $$
+BEGIN
+  SELECT lt.name INTO NEW.library_type_name
+  FROM libraries l
+  JOIN library_types lt ON l.library_type_id = lt.id
+  WHERE l.id = NEW.library_id;
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+CREATE TRIGGER set_library_type_name_on_insert
+  BEFORE INSERT ON media_items
+  FOR EACH ROW
+  EXECUTE FUNCTION set_library_type_name();
+
 -- Add GIN indexes for pg_trgm fuzzy search performance
 CREATE INDEX IF NOT EXISTS idx_media_items_author_trgm
   ON media_items USING GIN (author gin_trgm_ops);