feat(bounds): a `noise` mark, because a defect between two tracks belonged to neither

PLN, auditioning CosmicFest: "at 22:42 its end of reose_rouge, theres a loud blip
noise, at 22:44.9 its the start of rose rouge, could we cut noise and blend
better?"

The lab could only ever answer one question — where does the next track start —
so garbage living in the 2.9 s BETWEEN two tracks had nowhere to go. It survived
as prose in a comment box, which no downstream tool reads.

`n` marks the playhead as noise and deliberately leaves the cut call untouched: a
blip between two tracks is not an opinion about where either begins, and forcing
it through the cut field would corrupt the one number the mastering chain trusts.
`N` clears them, because a mis-tapped defect marker you cannot remove is worse
than no marker at all.

They render in warm orange, distinct from every existing mark colour: those are
all CANDIDATES for a cut, and this one is the opposite — a place to avoid.

Exported from both the decided and skipped blocks, so a seam PLN rejects can still
carry "and there is garbage at 22:42". That combination is exactly what happened
here and exactly what the old export could not represent.

armada/ui/src/bounds/BoundaryLab.tsx

@@ -37,7 +37,14 @@ interface Boundary {
 }
 interface BoundsDoc { gig: string; title: string; pad: number; boundaries: Boundary[] }
 
+// `noise` came from PLN auditioning CosmicFest: "at 22:42 its end of reose_rouge,
+// theres a loud blip noise, at 22:44.9 its the start of rose rouge, could we cut
+// noise and blend better?" — a defect in the 2.9 s BETWEEN two tracks, belonging
+// to neither. Until now the lab could only answer "where does the next track
+// start", so a transition carrying garbage had nowhere to be recorded, and the
+// note survived only as prose in a comment box.
 const MARK_COLOR: Record<string, string> = {
+  noise: 'rgba(255, 96, 64, 0.95)',     // a defect, not a candidate — warm and loud
   takeover: 'rgba(217, 0, 255, 0.9)',   // brand magenta — the one to try first
   mid: 'rgba(120, 170, 255, 0.75)',
   onset: 'rgba(120, 170, 255, 0.45)',
@@ -46,7 +53,7 @@ const MARK_COLOR: Record<string, string> = {
   nominal: 'rgba(255, 255, 255, 0.35)',
 }
 
-type Call = { t: number | null; comment: string; source: string }
+type Call = { t: number | null; comment: string; source: string; noise?: number[] }
 
 export function BoundaryLab({ gig }: { gig: string }) {
   const [doc, setDoc] = useState<BoundsDoc | null>(null)
@@ -75,13 +82,16 @@ export function BoundaryLab({ gig }: { gig: string }) {
 
   const markers = useMemo(() => {
     if (!b) return []
-    const all = [...b.marks, { key: 'nominal', label: 'nominal', t: b.nominal }]
+    const mine = (calls[b.track]?.noise ?? []).map((t, n) => ({
+      key: 'noise', label: `noise ${n + 1}`, t,
+    }))
+    const all = [...b.marks, ...mine, { key: 'nominal', label: 'nominal', t: b.nominal }]
     return all.map((m) => ({
       t: toClip(m.t),
       label: m.label,
       color: MARK_COLOR[m.key] ?? MARK_COLOR.nominal,
     }))
-  }, [b, toClip])
+  }, [b, toClip, calls])
 
   const jump = useCallback((tMaster: number, lead = 4) => {
     // land a few seconds BEFORE the candidate: a cut is judged by what leads
@@ -101,6 +111,21 @@ export function BoundaryLab({ gig }: { gig: string }) {
       if (e.key === 'j') setI((v) => Math.min(doc.boundaries.length - 1, v + 1))
       else if (e.key === 'k') setI((v) => Math.max(0, v - 1))
       else if (e.key === 'Enter' && b) setCall(toMaster(now), 'playhead')
+      // `n` marks garbage AT the playhead and leaves the cut call untouched: a
+      // blip between two tracks is not an opinion about where either begins.
+      else if (e.key === 'n' && b) {
+        const t = Number(toMaster(now).toFixed(2))
+        setCalls((c) => {
+          const cur = c[b.track] ?? { t: null, source: 'noise', comment: '' }
+          const noise = [...(cur.noise ?? []), t].sort((x, y) => x - y)
+          return { ...c, [b.track]: { ...cur, noise } }
+        })
+      }
+      // `N` clears them, because a mis-tapped defect marker you cannot remove is
+      // worse than none.
+      else if (e.key === 'N' && b) {
+        setCalls((c) => (c[b.track] ? { ...c, [b.track]: { ...c[b.track], noise: [] } } : c))
+      }
     }
     window.addEventListener('keydown', onKey)
     return () => window.removeEventListener('keydown', onKey)
@@ -120,7 +145,10 @@ export function BoundaryLab({ gig }: { gig: string }) {
       decided: Object.fromEntries(
         Object.entries(calls)
           .filter(([, c]) => c.t !== null)
-          .map(([k, c]) => [k, { start: Number(c.t!.toFixed(2)), source: c.source, note: c.comment }]),
+          .map(([k, c]) => [k, {
+            start: Number(c.t!.toFixed(2)), source: c.source, note: c.comment,
+            ...(c.noise?.length ? { noise: c.noise } : {}),
+          }]),
       ),
       // Skipped boundaries keep their NOTE. They used to export as bare integers,
       // which silently threw away the most valuable thing in the file: PLN skipped
@@ -134,7 +162,10 @@ export function BoundaryLab({ gig }: { gig: string }) {
       skipped: Object.fromEntries(
         Object.entries(calls)
           .filter(([, c]) => c.t === null)
-          .map(([k, c]) => [k, { source: c.source, note: c.comment }]),
+          .map(([k, c]) => [k, {
+            source: c.source, note: c.comment,
+            ...(c.noise?.length ? { noise: c.noise } : {}),
+          }]),
       ),
     }
     const url = URL.createObjectURL(new Blob([JSON.stringify(out, null, 1)], { type: 'application/json' }))
@@ -283,7 +314,7 @@ export function BoundaryLab({ gig }: { gig: string }) {
       </section>
 
       <p className="mt-6 font-mono text-[10px] text-ink-faint/70">
-        j/k next-prev · space play/pause · Enter = take the playhead · drag to loop a span ·
+        n = mark noise (N clears) · j/k next-prev · space play/pause · Enter = take the playhead · drag to loop a span ·
         clip is ±{doc.pad}s around the current cut, all exported times are master time
       </p>
     </div>