fix: #64 catalog quality

[evenkkl]

Closes #64

Summary

• Checked the MusicBrainz snapshot and the imported catalog (516 albums with the sample seed) for duplicate albums, missing metadata, artist and genre links, and track order.
• MusicBrainz writes hyphens as U+2010, so searches like "esa-pekka" or "switched-on" found nothing. The importer now stores ASCII hyphens and collapses whitespace in titles, artist names, genres and tracks.
• Artists are now shown in credit order ("Bob James, David Sanborn") instead of the order their rows happened to be created. New album_artist.position column (migration 0004). The loader orders by it.
• A reimport now replaces artist links, genre links and tracks that the snapshot no longer has, instead of keeping the old ones next to the new ones. Artists and genres the import leaves unused are removed. Album IDs, reviews and crate items are not touched.
• Added a "Catalog quality (Validate and refine the real album catalog #64)" section to the README with the checks and remaining limitations, and updated data-model and AI usage docs.

Findings

• No real duplicates. The three "Color Humano" albums are three different releases (1972-1974) by the same band, kept as separate albums.
• Every sort was paged through the whole catalog with no gaps or repeats, and facet counts match the filtered totals. All album detail pages load with tracks in order.
• Remaining limitations (documented): only 50 of 500 albums have a tracklist, 7 have no release year, search is not accent-insensitive, and artists are matched by name. Covers, country, E2E tests and final docs are left to Album cover images #23, Country facet and country filter #25, Playwright E2E journey + axe-core #20 and README and docs polish for peer review #26.

Verification

• pnpm format:check
• pnpm lint
• client and server typecheck
• 107 client tests and 90 server tests (new: hyphen and whitespace cleanup, reimport that changes artists, genres and tracks while keeping reviews and crate items)
• pnpm -r build
• PostgreSQL integration tests pass locally against PGlite. Seed + import + reimport was run on a local database and checked through the GraphQL API. Not yet checked in a browser or on PostgreSQL 18.
• The deploy runs migrations and the import, so the VM catalog gets the fixes on the next deploy.