chore(central-ripout 2d-i): relocate the fire engine + renderer out of central/

Moves the last two live files out of the retired-Central folder. central/ is
now EMPTY and deleted entirely (incl. __init__.py).

- fire-fusion engine (ingest_hotspot_pixel + the growth/cluster/spotting
  engine) → env/fire_fusion.py, next to its sole consumer env/firms.py.
- wildfire text renderer (_render + its live helpers) → env/fire_render.py.

THE COUPLING RESOLVED: firms_handler._handle_pass_boundary had a LAZY import
inside a function body — `from meshai.central.wfigs_handler import _render` —
sitting on the live FIRMS fire-growth path. It is now a normal top-of-file
import (`from meshai.env.fire_render import _render`), visible and greppable.

PURE MOVE — no behavior change:
- The parity oracle (test_fire_refactor.py) PASSES UNCHANGED (only its import
  paths updated) — proving the fire wire output is byte-for-byte identical
  before and after. Fire alerts say exactly what they said.
- handle_firms / handle_wfigs (dead entrypoints, only caller was the deleted
  consumer.py) were KEPT and moved rather than dropped — the wording-cleanup
  PR removes them deliberately. "When unsure, keep."
- fire_render.py's geo-helper imports still point at central_normalizer — that
  file's split is a SEPARATE PR; carried the imports along, did not touch it.

Consumers + test import paths rewired. Full suite: 2059 passed, 0 failed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

work/tests/test_fire_tracker_phase3.py

@@ -71,7 +71,7 @@ def test_pass_close_stamps_perimeter_geojson():
     """Pass A: 6 pixels in a hex around the seeded center. First pixel
     of pass B triggers boundary close -> perimeter_geojson written for
     pass A as a closed GeoJSON Polygon."""
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
     from meshai.persistence import get_db
 
     center_lat, center_lon = 42.500, -114.500
@@ -121,7 +121,7 @@ def _seed_pass_a_hex_then_close(*, irwin_id, center_lat, center_lon,
                                   start_now=1780747200):
     """Helper: seed a fire + 6 hex-vertex pass A pixels. Caller follows up
     with a pass B pixel to trigger boundary close + perimeter write."""
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
     _seed_fire(irwin_id=irwin_id, lat=center_lat, lon=center_lon,
                  name=irwin_id)
     for i in range(6):
@@ -138,7 +138,7 @@ def _seed_pass_a_hex_then_close(*, irwin_id, center_lat, center_lon,
 def test_pixel_2mi_ne_of_perimeter_emits_spotting():
     """Pass B pixel 2 mi NE of pass A's perimeter centroid fires
     wildfire_spotting with the correct distance + direction."""
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
     from meshai.persistence import get_db
 
     center_lat, center_lon = 43.000, -115.000
@@ -188,7 +188,7 @@ def test_pixel_2mi_ne_of_perimeter_emits_spotting():
 
 
 def test_pixel_inside_perimeter_no_spotting():
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
 
     center_lat, center_lon = 43.500, -114.500
     _seed_pass_a_hex_then_close(irwin_id="ID-SPOT-003",
@@ -223,7 +223,7 @@ def test_pixel_inside_perimeter_no_spotting():
 
 
 def test_second_spotting_within_cooldown_suppressed():
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
 
     center_lat, center_lon = 44.000, -116.000
     _seed_pass_a_hex_then_close(irwin_id="ID-SPOT-004",
@@ -257,7 +257,7 @@ def test_second_spotting_within_cooldown_suppressed():
 
 
 def test_spotting_refires_after_cooldown():
-    from meshai.central.firms_handler import handle_firms
+    from meshai.env.fire_fusion import handle_firms
 
     center_lat, center_lon = 44.500, -116.500
     _seed_pass_a_hex_then_close(irwin_id="ID-SPOT-005",
@@ -286,7 +286,7 @@ def test_spotting_refires_after_cooldown():
 
 
 def test_convex_hull_basic():
-    from meshai.central.firms_handler import _convex_hull
+    from meshai.env.fire_fusion import _convex_hull
     pts = [(0, 0), (1, 0), (1, 1), (0, 1), (0.5, 0.5)]
     hull = _convex_hull(pts)
     assert (0.5, 0.5) not in hull
@@ -294,7 +294,7 @@ def test_convex_hull_basic():
 
 
 def test_point_in_polygon_basic():
-    from meshai.central.firms_handler import _point_in_polygon
+    from meshai.env.fire_fusion import _point_in_polygon
     square = [(0, 0), (0, 10), (10, 10), (10, 0)]  # (lat, lon)
     assert _point_in_polygon((5, 5), square) is True
     assert _point_in_polygon((15, 5), square) is False
@@ -303,7 +303,7 @@ def test_point_in_polygon_basic():
 
 def test_geojson_round_trip_via_hull():
     """Hull -> GeoJSON -> parse -> ring shape sane."""
-    from meshai.central.firms_handler import _convex_hull, _hull_to_geojson
+    from meshai.env.fire_fusion import _convex_hull, _hull_to_geojson
     hull = _convex_hull([(0, 0), (1, 0), (0, 1), (1, 1)])
     raw = _hull_to_geojson(hull)
     parsed = json.loads(raw)