feat(simulation): climate-derived fields + frozen 17-zone morphology (T-1025, T-1027)

T-1025 (D-239 §2) — climate-derived fields, all from the temperature(+moisture)
primitive:
- precipitation_class + glaciation_grade re-keyed to (temperature_c, moisture_q)
  inputs (were keyed off raw body params); river_threshold signature follows.
- New VegetationClass (Absent/Barren/Scrub/Forest/RiparianScrub/RiparianThicket)
  + derive_vegetation: treeline bands x elevation, structural Forest->Scrub->Barren
  no-skip, riparian 1-3 tile band; airless (temp None) -> Absent.
- 21 tests.

T-1027 (D-239 §5/§6/§7) — morphology classifier:
- FROZEN 17-zone MorphologyZone enum exactly per D-239 §6 (OpenOcean..Wetland,
  repr(u8) pinned). Removed legacy Sea/CoastalLowland/Island/Canyon/Unknown;
  all consumers (skeleton_gen street_topology) remapped to nearest D-239 zone.
- 8-family gated decision tree (LavaField..AlluvialPlain fallback) over integer
  inputs; hard gates: Fjord>=GlaciationGrade2, LavaField=Volcanic tectonic,
  lithology slope/form laws (§8). 4 sub-classification zones (TidalFlat,
  Estuarine, Alpine, Wetland) derived from family + elevation/water.
- Build-time compatibility-matrix invariant tests (§7): MeanderReach<->Volcanic
  and Volcanic<->Fjord forbidden adjacencies structurally prevented by gate order.
- 13 tests incl 17-variant completeness + discriminant pinning.

D-010 integer discipline throughout. cargo test 1534 pass, clippy -D warnings
clean, fmt clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/src/atlas/skeleton_gen.rs

@@ -1046,19 +1046,31 @@ enum Topology {
 }
 
 fn street_topology(m: &MorphologyZone) -> Topology {
+    // D-234 morphology-gated trunk topology.
+    // Updated for D-239 §6 frozen 17-zone vocabulary (T-1027).
     match m {
-        MorphologyZone::Fjord | MorphologyZone::Canyon | MorphologyZone::MountainPass => {
-            Topology::Ribbon
-        }
+        // Ribbon: linear/constrained terrain — follow the single axis.
+        MorphologyZone::Fjord
+        | MorphologyZone::CliffCoast
+        | MorphologyZone::MountainPass
+        | MorphologyZone::Alpine
+        | MorphologyZone::ValleyFloor => Topology::Ribbon,
+
+        // HubSpoke: water-enclosed or island-like contexts — radiate from a centre.
         MorphologyZone::Delta
+        | MorphologyZone::Estuarine
         | MorphologyZone::OpenOcean
         | MorphologyZone::Lake
-        | MorphologyZone::Sea
-        | MorphologyZone::Island => Topology::HubSpoke,
+        | MorphologyZone::DuneStrand
+        | MorphologyZone::TidalFlat => Topology::HubSpoke,
+
+        // Mesh: flat/open terrain — any pattern.
         MorphologyZone::AlluvialPlain
         | MorphologyZone::MeanderReach
-        | MorphologyZone::CoastalLowland
-        | MorphologyZone::Unknown => Topology::Mesh,
+        | MorphologyZone::RiverBank
+        | MorphologyZone::BraidedPlain
+        | MorphologyZone::Wetland
+        | MorphologyZone::Volcanic => Topology::Mesh,
     }
 }
 
@@ -1748,7 +1760,7 @@ mod tests {
     #[test]
     fn hub_spoke_shares_a_common_node() {
         let aps = derive_access_points(&[0, 2, 4, 6], &[]);
-        let corridors = derive_corridors(&aps, &MorphologyZone::Island);
+        let corridors = derive_corridors(&aps, &MorphologyZone::OpenOcean);
         // Every spoke touches the hub.
         let hub = central_node(&aps) as u16;
         assert!(corridors.iter().all(|c| c.from == hub || c.to == hub));
@@ -1771,14 +1783,14 @@ mod tests {
         let inland = subdivide_block_footprints(
             70,
             &BulkClass::NonPhysical,
-            &MorphologyZone::CoastalLowland,
+            &MorphologyZone::RiverBank,
             None,
             SeedChain::root(3),
         );
         let quay = subdivide_block_footprints(
             70,
             &BulkClass::NonPhysical,
-            &MorphologyZone::CoastalLowland,
+            &MorphologyZone::RiverBank,
             Some(Edge::North),
             SeedChain::root(3),
         );
@@ -1796,14 +1808,14 @@ mod tests {
         let inland = subdivide_block_footprints(
             10,
             &BulkClass::BulkSolid,
-            &MorphologyZone::CoastalLowland,
+            &MorphologyZone::RiverBank,
             None,
             SeedChain::root(11),
         );
         let quay = subdivide_block_footprints(
             10,
             &BulkClass::BulkSolid,
-            &MorphologyZone::CoastalLowland,
+            &MorphologyZone::RiverBank,
             Some(Edge::North),
             SeedChain::root(11),
         );