Parse batch number and date from upload filename for live API lookup

SPEC.md

@@ -13,10 +13,10 @@ Daily cutoff @ HH:MM resets batch numbering. RK3588 hardware.
 - `numpy<2` (rknn-toolkit-lite2 incompatible with numpy≥2)
 - `PYTHONNOUSERSITE=1` ! set or venv breaks
 - SQLite for persistence, JSON file for active-batch state
-- Flask on port 5000 (dashboard) + 5002 (recounting), systemd supervision
+- Flask on port 5000 (dashboard) + 5002 (recounting) + 5003 (upload recounting), systemd supervision
 - `counter_live.py` ⊥ run on RK3588 — Jetson TensorRT artifact, ! port target
 - `counter_live_rknn_bytetrack.py` — reference for C++ port, this is what systemd runs
-- Single deployment: `counter_live_rknn_bytetrack.py` + `counter_dashboard.py` + `recounting_dashboard.py`
+- Single deployment: `counter_live_rknn_bytetrack.py` + `counter_dashboard.py` + `recounting_dashboard.py` + `recounting_dashboard_upload.py`
 - `go2rtc` ! running for recounting MP4 streaming (port 1984)
 
 ## §I — Interfaces
@@ -63,6 +63,14 @@ env: RECOUNT_API_URL → base URL of recounting counter API (second node)
 env: GO2RTC_API_URL → go2rtc REST API (default http://localhost:1984)
 env: GO2RTC_STREAM_NAME → go2rtc stream name for recount preview (default "recount")
 ```
+
+### Upload recounting dashboard config
+```
+env: RECOUNTING_UPLOAD_PORT → port for upload UI (default 5003)
+env: UPLOAD_DIR → dir for uploaded MP4s (default <repo>/uploads)
+env: RECOUNT_CMD → replay command template with {path} placeholder (default "bytetrack-counter config.env --source {path}")
+env: RECOUNTING_UPLOAD_TEMPLATE → template (default recounting_upload.html)
+```
 ```
 
 ### SQLite
@@ -107,6 +115,22 @@ api: GET /api/download-mp4?file=<path> → download selected MP4
 api: POST /api/start-recount {path} → reset recount counter + launch ffmpeg RTSP, return {stream_url}
 api: POST /api/stop-recount → kill ffmpeg + clear current file
 ```
+
+### Upload recounting dashboard
+```
+api: GET / → upload recounting HTML (template via RECOUNTING_UPLOAD_TEMPLATE env var)
+api: POST /api/upload → multipart .mp4 (≤512MB), saved as original filename in UPLOAD_DIR; returns {name, path, size}
+api: GET /api/uploads → list uploaded MP4s sorted by mtime desc → [ {name, path, size, mtime} ]
+api: POST /api/delete-upload {path} → delete uploaded MP4 (path restricted to UPLOAD_DIR)
+api: POST /api/start-recount {path} → reset recount API then launch RECOUNT_CMD (path shlex-quoted); START RECOUNT disabled until upload completes
+api: POST /api/stop-recount → kill recount process + clear current file
+api: GET /api/state → {streaming, file, file_name, stream_url, batch_number, batch_date}
+api: GET /api/proxy-stream → proxy MJPEG from RECOUNT_API_URL:/api/live-video (same-origin)
+api: GET /api/live-progress → proxy to LIVE_API_URL:/api/current-batch
+api: GET /api/recount-progress → proxy to RECOUNT_API_URL:/api/current-batch
+api: GET /api/batch-result?file=<path> → parse batch num + date (YYYY-MM-DD) from filename batch_XX_YYYYMMDD_HHmmSS.mp4, query live API /api/day-detail/<date>, fallback recent-batches
+api: GET /api/download-mp4?file=<path> → download selected MP4
+```
 ```
 
 ## §V — Invariants
@@ -132,6 +156,7 @@ V17: tracks pruned after TRACKED_PRUNE_SEC (default 300s) without update
 V18: .env missing → scripts fail at import (os.getenv falls back to defaults, may mismatch)
 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
 ```
 
 ## §T — Tasks
@@ -152,6 +177,7 @@ T11|x|reduce live-counter poll interval 2000→200ms for real-time feel|
 T12|x|add recounting dashboard — dual-API counter panels, MP4 browser, go2rtc streaming|
 T13|x|add template system — DASHBOARD_TEMPLATE env var selects dashboard.html|lamborghini|tesla|
 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
 ```
 
 ## §B — Bugs