Translate the whole project to English and fix outdated comments and help

Comments, docstrings, logs, CLI help, map UI, legends, PDF sheet, scripts,
compose files and AGENTS.md are now English. Data keys stay unchanged
(relief_oriente, densite_sol, visualisations/, API JSON keys, link params).
Wrong comments and help defaults found along the way are corrected.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitignore

@@ -1,15 +1,15 @@
-# Fichiers de données LiDAR (trop lourds pour git)
+# LiDAR data files (too heavy for git)
 *.laz
 *.las
 *.copc.laz
 
-# Résultats générés
+# Generated results
 output/
 output-webapp/
 output-maps/
 input/
 
-# Fichiers temporaires
+# Temporary files
 temp/
 *.tmp
 *.temp
@@ -27,7 +27,7 @@ build/
 .coverage
 htmlcov/
 
-# Interface bâchée dans l'image (régénérée au build, cf. Dockerfile.maps)
+# Interface baked into the image (regenerated at build time, see Dockerfile / Dockerfile.maps)
 lidar_pipeline/mapserve_assets/
 
 # Docker
@@ -44,27 +44,27 @@ lidar_pipeline/mapserve_assets/
 # Logs
 *.log
 
-# Fichiers de configuration locaux
+# Local configuration files
 .env
 .env.local
 
 
-# Données et artefacts internes (jamais dans le dépôt)
+# Internal data and artefacts (never in the repository)
 data/
 .swival/
 audit-findings/
 notebooks/
 
-# Éventuels fichiers de cache matplotlib
+# Possible matplotlib cache files
 matplotlibrc
 output-test/
 
-# Maquettes et suivi des sessions de brainstorming / SDD
+# Mock-ups and brainstorming / SDD session tracking
 .superpowers/
 
-# Plans et specs de sessions de travail (internes)
+# Work-session plans and specs (internal)
 docs/superpowers/
 .playwright-mcp/
 
-# Override local de la carte légère (modèle : docker-compose.maps.override.yml.example)
+# Local override of the lightweight map (template: docker-compose.maps.override.yml.example)
 docker-compose.maps.override.yml