Introduce a shared database schema library for Drizzle ORM and
configure its TypeScript build settings. Move the canonical schema
into libs/shared/database/src/lib/schema.ts and expose strong
typing and table definitions for playlists, categories, content,
recently_viewed and favorites. Add tsconfig.lib.json to set
outDir, declaration output and node types for the shared lib.
Keep apps/electron-backend compatibility by re-exporting the
schema and types from the new shared library (apps/electron-backend
now imports the shared definitions rather than duplicating them).
These changes centralize the database schema as a single source
of truth, prevent duplication, and enable read-only consumers
(e.g. agent-backend) to depend on compiled type declarations.
4gray