feat(v3 library): persistent "no match" badge + Unmatched quick filter

[ChrisBeWithYou]

Makes the metadata misses visible and reachable — the two follow-ups to the Refresh-Metadata batch (#764). Independent of the Fix-metadata popup stack; branches off main.

The gap: the batch paints a per-tile "no match" only while a pass runs, then clears it — so at rest you can't see which songs (the ~640 city-pop imports) never matched.

Persistent per-card "No match" badge

• query_page now marks each row unmatched — a cheap match_state='failed' set-membership over the page (like favs/estd), so no N+1.
• enrichBadge paints a subtle resting marker on those cards (right-click → fix by hand). It's tracked in a _unmatched set so a batch tile clearing falls back to the resting badge instead of wiping it; a live batch tile still wins while a pass runs (they never coexist).

"Unmatched" quick filter

• A local-only Unmatched toolbar toggle: one click applies the same filter as the drawer's Match → Unmatched (match_state='failed'), re-queries, and reflects active state — so the no-match pile is one click from the batch, without digging into the filter drawer.

Testing

• query_page flags a failed row (unmatched: true) and not a matched one; the match=unmatched filter returns only the failed song. test_library_filters + keyset + enrichment suites green (67). node --check clean; reuses existing utility classes (no CSS regen).

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added persistent No match (unmatched) badges on song cards for items that failed metadata matching.
  • Added an Unmatched quick filter to show only songs with no metadata match.

• Bug Fixes

  • Song cards retain the no-match indicator across metadata refreshes, instead of clearing when temporary batch tile state is gone.

• Tests

  • Added coverage for the unmatched flag behavior and the match=unmatched quick filter results.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 502de02 and 9b3431d.

📒 Files selected for processing (1)

• static/v3/songs.js

🚧 Files skipped from review as they are similar to previous changes (1)

• static/v3/songs.js

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📝 Walkthrough

Walkthrough

Adds a backend unmatched flag for failed enrichment matches, surfaces it in library query results, and updates the Songs UI to show a persistent no-match badge plus an Unmatched filter toggle. A test covers the flag and filter behavior.

Changes

Persistent Unmatched Badge and Filter

Layer / File(s)	Summary
Backend unmatched flag computation server.py	Adds MetadataDB._unmatched_set(filenames) using chunked SQL IN queries to find songs in 'failed' enrichment state, and wires it into query_page to set unmatched on each returned song card.
Persistent badge rendering and toolbar filter static/v3/songs.js	Extends enrichBadge with an unmatched flag and _unmatched tracking set to render a resting nomatch badge with tooltip, passes song.unmatched into card rendering, and adds an Unmatched toolbar button with visibility logic and a toggleUnmatchedFilter() handler that toggles the match filter and reloads the grid.
Test for unmatched flag and quick filter tests/test_library_filters.py	Adds a test seeding matched and failed rows, asserting the unmatched flag, and verifying /api/library?match=unmatched returns only the unmatched song.

Estimated code review effort: 2 (Simple) | ~12 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Browser
  participant songsjs as songs.js
  participant Server
  participant MetadataDB

  Browser->>songsjs: click `#v3-songs-unmatched`
  songsjs->>songsjs: toggleUnmatchedFilter()
  songsjs->>Server: reload() -> GET /api/library?match=unmatched
  Server->>MetadataDB: _unmatched_set(filenames)
  MetadataDB-->>Server: failed filenames set
  Server-->>songsjs: songs with unmatched flag
  songsjs->>songsjs: enrichBadge(key, song.unmatched)
  songsjs-->>Browser: render nomatch badge

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Possibly related PRs

• got-feedBack/feedBack#764: Shares the same enrichment match-state and per-card metadata refresh badge machinery that the unmatched badge feature builds on.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main v3 library changes: persistent no-match badges and the new Unmatched quick filter.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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• Commit unit tests in branch feat/v3-unmatched-visibility

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[ChrisBeWithYou]

📋 Merge order — metadata-curation epic (7 PRs)

1. feat(v3 library): "Fix metadata" popup — per-song override + lock, cover picker, MusicBrainz + AcoustID #777 — Fix-metadata popup
2. feat(v3 library): "Write to file" in the Fix-metadata popup #778 — Write to file
3. feat(v3 library): Match→Details "use these values" bridge #779 — Match→Details bridge
4. feat(v3 library): genre field in the Fix-metadata popup #780 — Genre in Details
5. feat(v3 library): persistent "no match" badge + Unmatched quick filter #781 — No-match badge + Unmatched filter (independent of 1–4 — fine to merge any time)
6. feat(v3 library): batch→popup handoff + English-base romaji (metadata-curation capstone) #782 — Batch→popup handoff + romaji (capstone)
7. feat(v3 library): searchable Cover Art Archive picker in Change-cover #783 — Searchable cover picker

#778–#780 are stacked (each based on the branch above), so GitHub re-points each to main automatically as the previous one merges — just merge #777 → #778 → #779 → #780 top-down. #781 is independent (base: main).

⚠️ Hold #782 and #783 until #777–#781 are all in main. #782's branch is a combined branch that already contains #777–#781, so merging it early would double-merge the stack. Once #777–#781 land, the author will rebase #782 (then #783) onto main — they shrink to just their own commits — and they're then ready to merge.

[ChrisBeWithYou]

Integration note — from a full-queue dry-run that merged every open org PR into a next-version test build.

Your persistent "No match" badge now overlaps #783 (the Fix-metadata capstone), which turns the same badge into a clickable hand-off into the Fix-metadata popup (data-meta-fix/fixable in songs.js). When both are merged, #783's clickable badge is the superset and #781's non-interactive badge is redundant.

Recommend: rebase on #783 and trim this PR down to just its unique surface — the Unmatched quick-filter button + toggleUnmatchedFilter + the Match filter section. Those merge cleanly and are the real contribution; the badge itself is already covered by #783. (In the dry-run I kept #783's clickable badge, and #781's filter + toggle slotted in intact.)