#688 fix: catalog-songs artistName filter must restrict rows (fixes empty valuation catalogs)

The bug (why valuation catalogs render empty)

A warm lead lands on /catalogs/{id}; the chat's useArtistCatalogSongs filters by the active sidebar artist and falls back to unfiltered only when the filtered query returns total_count === 0.

#681's LEFT join broke that filter. With song_artists/accounts LEFT-joined, a non-matching artistName .eq no longer drops rows — it just nulls the embed. So GET /api/catalogs/songs?...&artistName=<active artist> on a catalog by a different artist returns every row with artists: [null] and a non-zero count. The chat's fallback never fires (count ≠ 0), so:

• isCompleteSong fails on the [null] artist → all songs hidden ("Found N songs", empty list)
• the row renderer hits null.name → Cannot read properties of null (reading 'name') crash on "show all"

This masks the now-complete data from #684 (artists) + #687 (notes).

Fix

• When artistName is provided, inner-join song_artists/accounts so the filter restricts rows. A non-matching artist now returns 0 → the chat's existing fallback refetches the full catalog → songs render with their real artists.
• When no artistName, keep the LEFT join (api#681) so artist-less tracks still surface.
• Defensive: .filter(Boolean) the accounts so artists is never [null].

Verification (preview, real DB)

Greg Mendez catalog ccf07c48 (23 complete songs):

• artistName=Gatsby Grace (non-matching) → before: 23 with [null]; after: 0 → chat falls back.
• artistName=Greg Mendez (matching) → 23 with real artists.
• no artistName → 23 with artists (LEFT preserved).

(Preview curl results in a follow-up comment.) Root-cause fix for recoupable/chat#1801.

🤖 Generated with Claude Code

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Summary by cubic

Fixes empty catalogs and a row crash in chat by making the catalog songs artistName filter restrict rows.

• Bug Fixes

  • Inner-join song_artists and accounts when artistName is set; keep LEFT joins when not filtering.
  • Filter out null accounts so artists is never [null].
  • Prevents hidden songs and the null.name crash while keeping artist-less tracks visible with no filter.

• Refactors

  • Prettier-format selectCatalogSongsWithArtists for consistency.