Add web map with zone generation API, side job queue, and restore historical DTM hole rendering

- webapp.py: FastAPI serving the continuous map (port 8973) with
  /api/preview, /api/generate and /api/status; tiles are downloaded
  from IGN and processed in a logged subprocess, tracked live in a
  side "File de génération" panel that survives page reloads
- fetch_ign.py: download missing 1 km LiDAR HD tiles from the IGN
  geoplateforme before processing
- index.py: tile thumbnails and 500 m subtiles are now invalidated by
  mtime so regenerating a tile refreshes its cached images; progress
  logging per tile
- dtm.py: back to the historical gap handling (small gaps filled by
  fillnodata only, larger holes left as nodata rendered black);
  lowest-return floor only via --bare-earth, IGN class selection via
  --ign-classes
- cli.py: positional input now optional (--rebuild-index works alone)
- docker-compose.yml: serve (GPU, port 8973) and process services;
  launch via docker compose only (documented in AGENTS.md/AGENTS.md)
- tests: 131 passing, incl. regressions for thumbnail staleness,
  --rebuild-index without input, and nodata rendering

lidar_pipeline/tests/test_pipeline.py

@@ -70,4 +70,99 @@ class TestLidarArchaeoPipeline:
         names = [f.name for f in files]
         assert "test.laz" in names
         assert "other.las" in names
-        assert "readme.txt" not in names
+        assert "readme.txt" not in names
+
+
+class TestDtmMethodSidecar:
+    """Méthode de classification enregistrée à côté du DTM (invalidation du cache)."""
+
+    def test_missing_sidecar_matches(self, tmp_path):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        input_dir = tmp_path / "input"
+        input_dir.mkdir()
+        pipeline = LidarArchaeoPipeline(str(input_dir), str(tmp_path / "output"), ground_method='csf')
+        # Aucun sidecar écrit → cache conservé (considéré compatible).
+        assert pipeline._dtm_method_matches("tileA", "") is True
+
+    def test_matching_method(self, tmp_path):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        input_dir = tmp_path / "input"
+        input_dir.mkdir()
+        pipeline = LidarArchaeoPipeline(str(input_dir), str(tmp_path / "output"), ground_method='csf')
+        pipeline._write_dtm_method("tileA", "")
+        assert pipeline._dtm_method_matches("tileA", "") is True
+
+    def test_different_method_invalidates_cache(self, tmp_path):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        input_dir = tmp_path / "input"
+        input_dir.mkdir()
+        out = str(tmp_path / "output")
+        LidarArchaeoPipeline(str(input_dir), out, ground_method='ign')._write_dtm_method("tileA", "")
+        csf = LidarArchaeoPipeline(str(input_dir), out, ground_method='csf')
+        assert csf._dtm_method_matches("tileA", "") is False
+
+    def test_write_dtm_method(self, tmp_path):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        input_dir = tmp_path / "input"
+        input_dir.mkdir()
+        pipeline = LidarArchaeoPipeline(str(input_dir), str(tmp_path / "output"), ground_method='smrf')
+        pipeline._write_dtm_method("tileA", "_r0p2")
+        sidecar = tmp_path / "output" / "DTM" / "tileA_dtm_r0p2_method.txt"
+        assert sidecar.exists()
+        assert sidecar.read_text(encoding="utf-8").strip() == "smrf"
+        assert pipeline._dtm_method_name("tileA", "_r0p2") == "smrf"
+        # Le sidecar est un fichier .txt : il ne gêne pas la recherche des DTM .tif.
+        dtm = tmp_path / "output" / "DTM" / "tileA_dtm_r0p2.tif"
+        dtm.touch()
+        assert [p.name for p in (tmp_path / "output" / "DTM").glob("*.tif")] == ["tileA_dtm_r0p2.tif"]
+
+    def test_force_images_regenerates_existing(self, tmp_path):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        input_dir = tmp_path / "input"
+        input_dir.mkdir()
+        pipeline = LidarArchaeoPipeline(str(input_dir), str(tmp_path / "output"), output_format='avif')
+        calls = []
+
+        def fake_ortho(dem_file, basename, vis_dir, resolution):
+            calls.append(basename)
+            return vis_dir / f"{basename}_ortho.avif"
+
+        pipeline.viz_steps = [('ortho', fake_ortho)]
+        vis_dir = tmp_path / "output" / "visualisations" / "tileA"
+        vis_dir.mkdir(parents=True)
+        (vis_dir / "tileA_ortho.avif").touch()
+        dtm = tmp_path / "dtm.tif"
+
+        # Image existante, pas de force → ignorée (pas de régénération).
+        pipeline.generate_all_visualizations(dtm, "tileA", resolution=0.5, vis_dir=vis_dir, force_images=False)
+        assert calls == []
+
+        # Image existante, force_images=True → régénérée.
+        calls.clear()
+        pipeline.generate_all_visualizations(dtm, "tileA", resolution=0.5, vis_dir=vis_dir, force_images=True)
+        assert calls == ["tileA"]
+
+class TestEffectiveGroundMethod:
+    def test_ign_label_encodes_classes(self):
+        """Les classes IGN sont encodées dans l'étiquette de cache (reclassification)."""
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            p = LidarArchaeoPipeline(tmpdir, tmpdir, ground_method='ign',
+                                     ign_classes="sol,unclassified")
+            assert p._effective_ground_method() == "ign_1_2"
+
+    def test_ign_default_label(self):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            p = LidarArchaeoPipeline(tmpdir, tmpdir, ground_method='ign')
+            assert p._effective_ground_method() == "ign"
+
+    def test_other_methods_unchanged(self):
+        from lidar_pipeline.pipeline import LidarArchaeoPipeline
+        import tempfile
+        with tempfile.TemporaryDirectory() as tmpdir:
+            p = LidarArchaeoPipeline(tmpdir, tmpdir, ground_method='smrf',
+                                     ign_classes="sol,unclassified")
+            assert p._effective_ground_method() == "smrf"