Phase 5: voice consistency pass

Tier-1 voice-consistency pass: whole-document LLM review surfacing passages
that read tonally out of place (formal/over-polished/paraphrased-too-closely),
as honey-decorated `voice` flags with no correction (awareness-only).

- internal/llm/voice.go: RunVoice sends the whole document (no TruncateDoc),
  MaxTokens 2048, 20s per-doc floor (VoiceInterval). Standalone voice prompt
  in prompts.go (not bundled with the grammar checkpoint, per spec).
- internal/suggestions: POST /api/docs/:id/voice. replacePending is now
  family-scoped (pendingScope) so grammar and voice never clobber each other's
  pending flags; both passes return the unified pending set. check/voice share
  one runPass helper. TestVoicePassCoexists covers both directions.
- Frontend: api.voiceDoc, useCheckpoint voicing/runVoice, honey "Check my
  voice" toolbar pill, breathing honey dot in StatusBar.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

web/src/App.tsx

@@ -17,7 +17,9 @@ export default function App() {
   const {
     suggestions,
     checking,
+    voicing,
     schedule: scheduleCheckpoint,
+    runVoice,
     removeSuggestion,
   } = useCheckpoint(currentDoc?.id ?? null)
 
@@ -185,10 +187,17 @@ export default function App() {
                     suggestions={suggestions}
                     onAccept={handleAccept}
                     onDismiss={handleDismiss}
+                    onVoiceCheck={runVoice}
+                    voicing={voicing}
                   />
                 </div>
               </div>
-              <StatusBar wordCount={wordCount} saveStatus={status} checking={checking} />
+              <StatusBar
+                wordCount={wordCount}
+                saveStatus={status}
+                checking={checking}
+                voicing={voicing}
+              />
             </>
           ) : (
             <div