implemented 15,12,18 didn't check 18

.github/copilot-instructions.md

@@ -55,6 +55,16 @@ Use project virtualenvs where available (`.venv312`, `.venv`, or `venv`) for bac
 - Media URL handling between project load paths should remain consistent to avoid format-specific regressions (especially WAV/MP3 behavior).
 - Export pipeline changes must preserve caption modes (`none`, `sidecar`, `burn-in`) and audio enhancement behavior.
 
+## Recent Changes
+
+### 2026-05-04 — Word text correction, low-confidence highlighting, audio normalization
+
+- **Word text correction (#015)**: Double-click any word in the transcript editor to edit its text inline. Press Enter to commit, Escape to cancel. State is updated in both `words[]` and `segments[]` arrays (segment text recomposed from updated words). Pure frontend; no backend changes needed.
+- **Low-confidence word highlighting (#012)**: Words with `confidence < threshold` (default 0.6, configurable in Settings panel) render with an orange dotted underline. Tooltip shows exact confidence percentage. Threshold is persisted in `localStorage` key `talkedit:confidenceThreshold`.
+- **Audio normalization (#018)**: New backend endpoint `POST /audio/normalize` in `backend/routers/audio.py`. Two-pass FFmpeg `loudnorm` (measure then apply) implemented in `backend/services/audio_cleaner.py:normalize_audio()`. Falls back to single-pass if measurement fails. Frontend UI in Export panel: target selector (YouTube -14, Spotify -16, Broadcast -23, etc.) with "Normalize" button.
+- **Store**: New `updateWordText(index, text)` action in `editorStore.ts` updates both `words[]` and recomputes `segments[].text`.
+- **Settings panel**: New confidence threshold slider (0–1 range).
+
 ## Update Rules (Important)
 
 When a task changes architecture, app wiring, commands, API shape, project schema, or major conventions, update this file before finishing.