feat(jamguide): Roadmap Jam Guide panel — shell, App mount, live assembly (tasks L-02, D-02)

Bottom-dock panel: collapsed header -> ~70vh, instrument+style tabs from KB registry,
matcher/position via match.js. Assembles RoadmapTrack + per-station ChordDiagram
thumbnails; reconciles playhead detected-loop index -> canonical KB station via
match.rotation; tap-to-enlarge voicings; auto-scroll active station; narrow reflow.
App.jsx change is additive (+10/-0) — audio callbacks/refs untouched. Critic PASS all 4.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/App.jsx

@@ -13,6 +13,7 @@ import { NOTES, detectKey, detectTopKeys, matchChordFromChroma, detectRepeatingP
 import ChordDetailModal from './components/ChordDetailModal'
 import CurrentJamPanel from './components/CurrentJamPanel'
 import LoopStation from './components/LoopStation'
+import JamGuide from './components/JamGuide'
 import { useLoopEngine } from './services/loopEngine'
 import settingIcon from './assets/setting-icon.png'
 
@@ -658,6 +659,15 @@ export default function App() {
         </button>
         {showTuner && <div className="border-t border-border"><Tuner /></div>}
       </div>
+
+      {/* ── Jam Guide — bottom dock (Roadmap) ── */}
+      <JamGuide
+        detectedProgression={detectedProgression}
+        keyInfo={effectiveKey}
+        chordHistory={chordHistory}
+        bpm={bpm}
+        currentChord={currentChord}
+      />
     </div>
   )
 }