Fixes#141
The repository metadata field was missing from the database schema, which
caused the metadata sync state (issues, PRs, releases, etc.) to not persist.
This resulted in duplicate issues being created every time a repository was
synced because the system couldn't track what had already been mirrored.
Changes:
- Added metadata text field to repositories table in schema
- Added metadata field to repositorySchema Zod validation
- Generated database migration 0008_serious_thena.sql
Root cause analysis:
1. Code tried to read/write repository.metadata to track mirrored components
2. The metadata field didn't exist in the database schema
3. On sync, metadataState.components.issues was always false
4. This triggered re-mirroring of all issues, creating duplicates
The fix ensures metadata state persists between mirrors and syncs, preventing
duplicate metadata (issues, PRs, releases) from being created in Gitea.
