Evilander/newamp

Expert-pass cleanup driven by a 10-reviewer parallel ultrareview of the 1.5.3 → 1.5.6 changeset. Five blockers, ten high-priority items, two cleanup passes — all applied and verified by smoke.

Structural fix

`npm run typecheck` runs in `prebuild`. The frontend has had zero type checking in CI since the project's start — `build:electron` only ran `tsc` against the electron tsconfig, and `build:vite` used esbuild which strips types without checking them. That's why 1.5.4 shipped an `AlbumSummary` literal missing required fields and 1.5.5 shipped despite strict-mode TypeScript. New `typecheck` script runs `tsc` against both tsconfigs; release builds now fail on type errors instead of letting them ship.

Real bugs fixed in shipped 1.5.6

• `engine.seek` false-positive warnings on every seekbar drag. The 1.5.4 diagnostic captured `target` in a closure but read `currentTime` at fire time. ~30 spurious warnings per drag. Now snapshots seekSeq + deck identity at schedule time and bails if anything changed.
• `AlbumsView` pendingNavigation literal had `undefined` rating fields. Caught by the new typecheck gate. Fix also hydrates the real album rating asynchronously.
• Wheel volume → settings.json sync writes flood. The 1.5.4 wheel-anywhere-over-viz handler made the whole canvas wheel-active; 60-120 sync `writeFileSync` calls per second on rapid scroll. Web Audio gain ramp stays synchronous; disk persist now debounces 250ms trailing.
• Pre-1.5.4 album ratings silently vanished. New one-shot backfill migration via a `library_meta` flag table.

Silent-failure hardening

• AlbumScoreInline rewritten: loud catch, write try/catch, write-generation guard for stale resolves, albumArtist fallback so empty-tag albums can be rated.
• AlbumsView.setAlbumScore write wrapped in try/catch matching the 1.5.6 read-path hardening; no more lying "Rated X 75/100" after a failed write.
• Visualizer disconnectAudio narrowed to the benign `InvalidAccessError | not connected` case; real graph corruption now logs at `console.error`.
• `setAlbumRatingScore` + `getAlbumRating` throw on missing input — caller can distinguish "successful clear" from "this call should never have been made."

Patterns

• Canonical `albumKey()` helper in `shared/album-key.ts`. Four inline rating sites collapsed to one.
• IPC argument order aligned to `(albumArtist, album)` everywhere; 7 call sites updated.
• COLLATE NOCASE ASCII-only caveat documented at schema + helper.

Smokes added/extended

• `rating-smoke` covers album_ratings round-trip (set/get/clear/NOCASE/persist), the explicit "must not touch track ratings" guarantee, `getAlbums()` after `album_ratings` rows exist (locks down the 1.5.4 LEFT JOIN ambiguous-column regression class), and throws on bad input.
• `ui-visualizer-smoke` adds FFT-sum liveness via a new `__newampSmoke.analyserFftSum` hook. Software WebGL drops shader paint so pixel deltas don't work, but the FFT path catches the load-bearing signal — if the analyser subtree is alive, FFT bytes are non-zero. Fixture extended from 4.2s to 30s.

Verification

`npm run typecheck` clean. Smoke battery green: library, album-art, keyboard, rating, visualizer, ui-visualizer, audio-limiter, replaygain, harmonic, sonic-atlas, album-random-sort, packaged-normal-launch. Windows binaries signed. SHA256SUMS + BUILD-PROVENANCE attached.

The 1.5.4 → 1.5.5 → 1.5.6 hotfix sequence happened because vite silently shipped TypeScript-invalid code, a silent `.catch(() => setAlbums([]))` made the SQL error look like "library is empty," and a smoke that asserted on a setup flag missed a broken render loop. All three failure modes now have structural prevention.