able to modify trim zones

FEATURES.md

@@ -8,13 +8,13 @@ Features are grouped by priority. Check off items as they are implemented.
 
 - [x] **Cut / Mute sections** — select a time range and choose to cut (remove entirely) or mute (silence audio while video continues). Cut sections show as red overlays, mute sections as transparent blue overlays on the timeline over the transcript text and audio waveform. Backend: `ffmpeg -af volume=0` for mute, time-based cutting for removal.
 
-- [ ] **Silence / pause trimmer (in progress)** — detect pauses using min duration (ms) + amplitude threshold (dB), then apply detected pauses as cut ranges. Initial endpoint: `/audio/detect-silence`; UI includes filter controls and an "Apply As Cuts" action.
+- [x] **Silence / pause trimmer (in progress)** — detect pauses using min duration (ms) + amplitude threshold (dB), then apply detected pauses as cut ranges. Initial endpoint: `/audio/detect-silence`; UI includes filter controls and an "Apply As Cuts" action.
 
-- [ ] **Operation-level undo for batch actions** — explicit undo entry for actions like "Apply Silence Trim" so one shortcut/click reverts the whole operation, while still allowing normal fine-grained undo/redo steps.
+- [x] **Operation-level undo for batch actions** — explicit undo entry for actions like "Apply Silence Trim" so one shortcut/click reverts the whole operation, while still allowing normal fine-grained undo/redo steps.
 
-- [ ] **Grouped silence-trim zones (editable batch)** — when pauses are applied, tag them as a batch (`trim_group_id`) so the user can: (1) delete all zones from that auto-trim pass at once, and (2) still select/resize/delete individual zones independently.
+- [x] **Grouped silence-trim zones (editable batch)** — when pauses are applied, tag them as a batch (`trim_group_id`) so the user can: (1) delete all zones from that auto-trim pass at once, and (2) still select/resize/delete individual zones independently.
 
-- [ ] **Edit silence-trim group settings after apply** — allow reopening a trim group and changing its detection settings (min pause ms, threshold dB, pre/post buffers), then reapplying updates to that group without affecting unrelated edits.
+- [x] **Edit silence-trim group settings after apply** — allow reopening a trim group and changing its detection settings (min pause ms, threshold dB, pre/post buffers), then reapplying updates to that group without affecting unrelated edits.
 
 - [ ] **Volume / gain control** — per-selection or global audio gain slider. Every editor has this. Descript users constantly complain it's missing. Backend: `ffmpeg -af volume=Xdb`.