Add multi-resolution support and remove PDF generation

- --resolution now accepts comma-separated values (e.g. 0.5,0.2)
- Additional resolutions get suffixed output dirs: basename_r0p2/
- DTM files are named basename_dtm_r0p2.tif for extra resolutions
- Ground classification is done once and shared across resolutions
- PDF report generation removed per user request
- Fix --file argument to accept full filenames with extensions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lidar_pipeline/dtm.py

@@ -402,7 +402,7 @@ def _repair_laz_with_laspy(input_laz, output_las):
         return False
 
 
-def create_dtm_fast(las_file, basename, dtm_dir, resolution, force=False):
+def create_dtm_fast(las_file, basename, dtm_dir, resolution, force=False, output_suffix=""):
     """Create DTM using fast binning method with gap filling.
 
     Args:
@@ -411,11 +411,12 @@ def create_dtm_fast(las_file, basename, dtm_dir, resolution, force=False):
         dtm_dir: Directory for output DTM GeoTIFF.
         resolution: Grid resolution in meters per pixel.
         force: If True, regenerate even if DTM already exists.
+        output_suffix: Suffix for output filename (e.g. '_r0p2' for additional resolutions).
 
     Returns:
         Path to output DTM GeoTIFF, or None on failure.
     """
-    output_tif = dtm_dir / f"{basename}_dtm.tif"
+    output_tif = dtm_dir / f"{basename}_dtm{output_suffix}.tif"
 
     if output_tif.exists() and not force:
         logger.info(f"  DTM déjà existant — fichier réutilisé: {output_tif.name}")