Translate the whole project to English and fix outdated comments and help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

README.md

@@ -90,10 +90,8 @@ the CPU (slower, same output).
 
 Tile IDs are the IGN grid coordinates in km (Lambert 93): `1037,6779` is the tile
 whose top-left corner is at X = 1,037 km, Y = 6,779 km. You can also skip the
-command line entirely: open the map, go to the **Génération** tab and draw a
-zone.
-
-> The user interface and log messages are in French; code identifiers are in English.
+command line entirely: open the map, go to the **Generate** tab and draw an
+area.
 
 ## How it works
 
@@ -131,7 +129,8 @@ flowchart LR
 - **Three view modes** — relief, precision, or *compare* with a draggable split bar.
 - **Relief intensity** slider (0.5×–2×), remembered per browser and carried in the link.
 - **Share** — the URL encodes position, mode, comparison and intensity.
-- **Use in JOSM / QGIS** button — copies the tile URL for the current layer.
+- **Use in JOSM / QGIS** — the Share tab lists the XYZ, TileJSON, WMTS and JOSM URLs,
+  with a **Copy** button for the chosen layer's tile URL.
 - Keyboard: `1`–`5` tabs, `P` next view mode, `Esc` deselect / collapse.
 - Works on phones: the panel becomes a three-height bottom sheet; GPS centring over HTTPS.