Add bounded terrain and flood analysis

frontend/README.md

@@ -598,6 +598,21 @@ pattern and a rectangle returns scenario-bound hectare/depth metrics. Raster
 GeoJSON export stays disabled. The UI never labels the maximum-depth area
 integral as current, permanent or concurrent water volume.
 
+In the Flanders workspace, DHMV and VMM products do not need to be
+pre-provisioned before they become usable. The explorer reads the governed
+backend registries, exposes DTM/DSM and all twelve VMM scenarios, and acquires
+only the municipality or rectangle the user explicitly analyses. The
+acquisition still runs through the backend Job and Dataset boundaries; the
+browser never contacts WCS directly. An exact repeat reuses the persisted
+request. A complete-Flanders raster request remains disabled by the regional
+size guard, while a complete municipality remains a valid bounded analysis.
+
+Selecting `Hoogte & reliëf` shows the source distinction before analysis:
+DTM represents terrain after removal of buildings and other objects; DSM
+represents the visible surface including buildings and vegetation. Selecting
+`Overstroming` shows mechanism, climate context and return period. The result
+therefore cannot be mistaken for an observed current water level.
+
 Regional VMM provisioning creates one scenario raster per municipality Area.
 For a municipality the explorer still uses only that exact Area-linked file.
 For the complete Kempen Area it presents the 28 VMM and DHMV partitions as one