Auto-on live preview when recount starts (all recounting templates)

SPEC.md

@@ -159,6 +159,7 @@ V18: .env missing → scripts fail at import (os.getenv falls back to defaults,
 V19: stream reconnect → reset motion detection state (prev_gray = None)
 V20: reset → delete STATE_FILE + touch {SHM_DIR}/.reset; batch_store._check_reset_signal() watches marker & clears in-memory state before next crossing
 V21: upload filename batch_XX_YYYYMMDD_HHmmSS.mp4 → batch# + date parsed; batch-result queries /api/day-detail/<YYYY-MM-DD> on live API
+V22: preview auto-on when recount running — enablePreview() on START RECOUNT + applyState streaming branch; manual toggle overrides; img.onerror retries cache-busted src while streaming
 ```
 
 ## §T — Tasks
@@ -181,6 +182,7 @@ T13|x|add template system — DASHBOARD_TEMPLATE env var selects dashboard.html|
 T14|x|harden reset API — separate SHM marker creation from state file cleanup; return 500 on SHM failure|V20
 T15|x|add upload recounting dashboard — MP4 upload, progress bar, RECOUNT_CMD replay|V21
 T16|x|add cross-dashboard header links — UPLOAD_DASHBOARD_URL (live→upload) & LIVE_DASHBOARD_URL (upload→live)|I.config
+T17|x|auto-on live preview when recount running — enablePreview() on START + applyState; onerror retry while streaming|V22
 ```
 
 ## §B — Bugs