Revert "Add clear GPS endpoint + frontend button"

This reverts commit ca77a29d7d.

tests/test_server.py

@@ -432,31 +432,6 @@ class TestDeleteAsset:
         assert response.status_code == 404
 
 
-class TestClearAssetGps:
-    """Clear GPS endpoint."""
-
-    def test_clear_gps_returns_204(self, client):
-        """Clear GPS returns 204 and sets lat/lng to null."""
-        r = client.post("/api/assets", json={
-            "machine_id": "GPS001", "name": "Has GPS",
-            "latitude": 28.5, "longitude": -81.3
-        })
-        asset_id = r.json()["id"]
-        response = client.delete(f"/api/assets/{asset_id}/gps")
-        assert response.status_code == 204
-
-        # Verify lat/lng are cleared
-        r2 = client.get(f"/api/assets/{asset_id}")
-        assert r2.status_code == 200
-        data = r2.json()
-        assert data["latitude"] is None
-        assert data["longitude"] is None
-
-    def test_clear_gps_not_found_returns_404(self, client):
-        response = client.delete("/api/assets/99999/gps")
-        assert response.status_code == 404
-
-
 # ─── Task 7: GET /api/assets/search?machine_id= ───────────────────────────