feat: unified config.yaml with extensible model presets (A-D data-driven, E/F ready)

- config.yaml canonical for stream/models/counting/batch/output/camera
- models.modes hold engines+class filters only; conf/iou/min_bbox in detection_params
- predict.py derives tracker roles structurally (no per-mode branching)
- dashboard mode switch validates + persists atomically to config.yaml
- .env keeps secrets/deployment only; zones.json geometry; tracker.yaml hyperparams
- batch_mode.json keeps manual/auto batch mode; legacy model_mode ignored w/ warning
- src/detection+tracking gain iou param (default 0.7 = no behavior change)

.env.example

@@ -1,24 +1,34 @@
-# Core variables for Karung Counter
+# .env — SECRETS & deployment-specific values ONLY (never commit real credentials).
+# Canonical config lives in config.yaml (paths, modes, counting knobs, batch, camera).
+# Zone polygons live in zones.json. Tracker hyperparams live in cfg/tracker.yaml.
+#
+# Legacy keys (MODEL_PATH, MODEL_MODE, BATCH_MODE_FILE, *_PATH overrides) are
+# still honoured when set, but deprecated — prefer config.yaml.
+
+# --- Output paths (override config.yaml output.* when set; legacy) ---
 OUTPUT_DIR=/opt/jetson-counter
 DB_PATH=/opt/jetson-counter/jetson_counter.db
 STATE_FILE=/opt/jetson-counter/current_batch.json
-BATCH_MODE_FILE=/opt/jetson-counter/batch_mode.json
 LIVE_STREAM_FRAME_PATH=/dev/shm/jetson-counter/live_frame.jpg
+
+# --- Identity / batch day ---
 CAMERA_NAME=CC1
 OBJECT_LABEL=karung-pakan
 DAILY_CUTOFF_TIME=06:00
+BATCH_MERGE_THRESHOLD_SECONDS=300
 
-# Dashboard variables
+# --- Dashboard (canonical home for these; read from env, NOT config.yaml) ---
 SECRET_KEY=change-me-in-production
 DASHBOARD_HOST=0.0.0.0
 DASHBOARD_PORT=5000
 OFFICE_PORT=5721
 FLASK_DEBUG=false
+SITE_NAME=LIVE
 
-# Stream URL
+# --- Stream (canonical home; read from env, NOT config.yaml) ---
 RTSP_URL=rtsp://user:pass@192.168.192.209:8554/camera_stream_640
 
-# Model pipeline mode: A=combined only; B=v4 truck + yolo11n sack+box;
-# C=A + yolo11n box-only (default); D=v4 truck + best sack-only + yolo11n box-only.
-# Dashboard switches persist here and apply on next service restart.
-MODEL_MODE=C
+# --- Deprecated: model pipeline mode now lives in config.yaml models.active_mode.
+# Dashboard switches persist there (atomic write, comments preserved) and apply
+# on next `karung-counter` restart. Only set this to temporarily override.
+# MODEL_MODE=C