refactor: consolidate counting config through src/config_loader

- config.yaml gains counting.max_reid_frames (200) + debounce_frames (8);
  CountingConfig + parsing + pinned-value test added
- predict.py load_zones() delegates to read_zone_polygons() (geometry only);
  legacy zones.json knob reads removed (config.yaml is canonical)
- run_prediction wires 5 more live knobs from cfg.counting.* (entry/exit
  overlap, tolerance_missing_frames, max_reid_frames, debounce_frames)
- delete deprecated src/config.py (v3 keys) + tests/test_config.py;
  src/main.py bridges onto unified config so the deprecated entrypoint
  keeps working
- 8 never-read globals (JARAK_ABSORBSI_GHOST, CAMERA_NOISE_DEADBAND, ...)
  left untouched — flagged for Phase 2 dead-code cleanup

Verified: pytest 21 passed; full pipeline runs on synthetic video
(engines load, 30 frames, clean finish).

tests/test_config_loader.py

@@ -39,6 +39,25 @@ def test_repo_config_loads_and_validates(repo_config_path):
         assert dp.min_bbox_area >= 0
 
 
+def test_counting_knobs_match_production_defaults(repo_config_path):
+    """All live counting knobs in predict.py must come from config.yaml."""
+    cfg = load_config(repo_config_path)
+    c = cfg.counting
+    assert c.confirm_delay_sec == 0.5
+    assert c.exit_confirm_delay_sec == 6.0
+    assert c.entry_overlap_threshold == 0.20
+    assert c.exit_overlap_threshold == 0.05
+    assert c.camera_noise_deadband == 50
+    assert c.duplicate_circle_radius == 30
+    assert c.min_valid_area == 15000
+    assert c.max_reid_transit_distance == 400
+    assert c.circle_stay_timeout_sec == 10.0
+    assert c.jarak_toleransi_duplikat == 30
+    assert c.tolerance_missing_frames == 1200
+    assert c.max_reid_frames == 200
+    assert c.debounce_frames == 8
+
+
 def test_mode_preset_only_filters_and_engines(repo_config_path):
     """Modes must not carry per-class conf/iou — those live in detection_params."""
     with open(repo_config_path) as f: