Merge remote-tracking branch 'origin/climate-morphology-layers'

governance/decisions/architecture.md

@@ -1771,6 +1771,7 @@ Technical foundation decisions that constrain implementation: engine, client-ser
 - **Raised by:** tile-derivation-contract workshop (Tyre — refinement chain, warp, determinism; Gestalt — 8 families, game-feel; Troblum — feasibility, warp precision, scale corrections; Miri — believability laws, vocabulary, lore reconciliation), lead-interviewed decisions + an adversarial verification pass, 2026-06-07.
 - **Dissent:** Tyre's initial cross-family elevation-blend was resolved against (prevent-at-source). Early-integer-truncation of the warp (raised against Gestalt's `ElevationDelta` ranges and by Tyre) was resolved against in favour of f64-to-voxel.
 - **Implementation note (T-1024, 2026-06-07):** §1 per-body `RIVER_THRESHOLD` is now a derived field (`derive_river_threshold`) on `RegionProfile`. §2 district temperature is a nullable `f32` on `RegionProfile` sampled from a per-region climate derivation (`derive_temperature_c`); moisture is a separate integer primitive (`derive_moisture_q`, 0–100). Both populate the `RegionProfile` carrier during the L4 cascade run. Climate inputs use a **hybrid strategy**: stellar luminosity and spectral class are sourced from the import pipeline (`bodies.axial_tilt_deg`, `star_systems.spectral_class`); greenhouse offsets and diurnal amplitudes are tunable at runtime via `server/data/climate_constants.toml` (source-canonical TOML, not hardcoded).
+- **Implementation note (T-1025/T-1027, 2026-06-08):** §6's frozen 17-zone `MorphologyZone` enum is realised in `server/src/simulation/generator.rs` (`repr(u8)`, discriminant-pinned). The §5 8-family gated classifier + §7 compatibility-matrix invariants live in `derive_morphology_zone` (`region_profile.rs`). **16 of the 17 zones are reachable at RegionProfile scale; `BraidedPlain` is the exception** — distinguishing it from `Delta` needs a lithology signal (§8 Gravel→braided) that `RegionProfile` does not carry, so `BraidedPlain` is **deferred to ChunkContext** sub-classification. The §7 compatibility invariant is enforced as a **classifier-gate-ordering** property (a build-time test that a single region cannot yield a forbidden pair), per §7's "build-time test" language; genuine cross-region sharp seams (cliff↔fjord, lithology faults) remain permitted. §2 climate-derived fields (`precipitation_class`, `glaciation_grade`, `vegetation_class`) all derive from the temperature(+moisture) primitive (T-1025).
 - **Cross-reference:** [D-227](#d-227) (derive-don't-store voxel model), [D-228](#d-228) (composite tile axes / cohesion / seasonal state), [D-210](#d-210) (temperature proxy — formalised), [D-203](#d-203) (BodyWorldState cache), [D-206](#d-206) (background analysis pass), [D-208](#d-208) (drainage / D8), [D-010](#d-010) (determinism), [D-234](#d-234) (street/footprint geometry — consumes morphology), [D-142](content.md#d-142) (zone types), [D-217](#d-217) (tile condition), [Q-102](../questions/architecture.md#q-102) (cohesion = the warp), [Q-103](../questions/architecture.md#q-103) (mutator schema — open), [Q-105](../questions/architecture.md#q-105) (seasonal/clock state — temperature/ElevationDelta forward contract)
 
 ---

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 => {
+        // Ribbon: linear/constrained terrain — follow the single axis.
-            Topology::Ribbon
+        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::DuneStrand
-        | MorphologyZone::Island => Topology::HubSpoke,
+        | MorphologyZone::TidalFlat => Topology::HubSpoke,
+
+        // Mesh: flat/open terrain — any pattern.
         MorphologyZone::AlluvialPlain
         | MorphologyZone::MeanderReach
-        | MorphologyZone::CoastalLowland
+        | MorphologyZone::RiverBank
-        | MorphologyZone::Unknown => Topology::Mesh,
+        | 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),
         );

server/src/simulation/generator.rs

@@ -946,38 +946,65 @@ pub struct DoorSpec {
     pub interior_descriptor: InteriorDescriptor,
 }
 
-/// Region-level morphology zone (D-228, D-232, D-234).
+/// Region-level morphology zone — D-239 §6 frozen 17-zone vocabulary (T-1027).
+///
+/// **FREEZE POINT**: this enum is the canonical freeze per D-239 §6.
+/// Adding, renaming, or removing a zone **requires a D-record amendment**
+/// (reviewer-enforced). Classifier tuning that merely re-classifies a region
+/// is NOT a vocabulary change and stays free.
+///
+/// Zones ≠ families. Four zones — TidalFlat, Estuarine, Alpine, Wetland —
+/// are derived sub-classifications (family + elevation/water-height), not
+/// distinct generator families.
 ///
 /// Shared by all tiles in a region; constrains street geometry (D-234)
 /// and acts as a soft weight on cultural-template eligibility (D-232).
 /// Carried on `CityGenerationContext` (D-233 amend to D-199).
+///
+/// Integer-discriminant, D-010 compliant. `repr(u8)` pins values for
+/// serialisation stability; append-only.
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, Default)]
+#[repr(u8)]
 pub enum MorphologyZone {
-    /// Steep-sided inlet — ribbon/hub-and-spoke streets only; pier geometry on water edges.
+    /// Deep-water ocean — hub-and-spoke; perimeter access priority.
-    Fjord,
+    OpenOcean = 0,
+    /// Lake body — hub-and-spoke; perimeter access toward water.
+    Lake = 1,
+    /// Tidal flat (sub-classification): low coastal plain exposed at low tide.
+    /// Derived from CliffCoast/AlluvialPlain family + tidal signal + low elevation.
+    TidalFlat = 2,
+    /// Dune strand — ribbon/hub-and-spoke; wind-aligned lot orientation.
+    DuneStrand = 3,
+    /// Cliff coast — ribbon only; vertical face at water edge.
+    CliffCoast = 4,
+    /// Fjord — ribbon/hub-and-spoke; pier geometry; requires GlaciationGrade ≥ 2.
+    Fjord = 5,
     /// River delta / braided channel — hub-and-spoke following channels; bridges as forced nodes.
-    Delta,
+    Delta = 6,
-    /// Meandering river reach — any pattern.
+    /// Estuarine (sub-classification): brackish tidal zone at river mouth.
-    MeanderReach,
+    /// Derived from Delta/AlluvialPlain family + tidal signal + low elevation.
+    Estuarine = 7,
     /// Flat alluvial plain — any pattern; primary default for plains settlements.
     #[default]
-    AlluvialPlain,
+    AlluvialPlain = 8,
-    /// Open ocean surface (deep-water context) — hub-and-spoke; perimeter access priority.
+    /// River bank — gentle approach; pier geometry on water-facing edges.
-    OpenOcean,
+    RiverBank = 9,
-    /// Lake shore — hub-and-spoke; perimeter access toward water.
+    /// Meandering river reach — any pattern.
-    Lake,
+    MeanderReach = 10,
-    /// Interior sea body.
+    /// Braided channel plain — hub-and-spoke; gravel/sand substrate.
-    Sea,
+    BraidedPlain = 11,
+    /// Valley floor — ribbon or mesh; enclosed by flanking slopes.
+    ValleyFloor = 12,
     /// Mountain pass terrain — ribbon only; elevation steps as block boundaries.
-    MountainPass,
+    MountainPass = 13,
-    /// Coastal lowland — any pattern; pier geometry on water-facing edges.
+    /// Alpine (sub-classification): above treeline high-altitude zone.
-    CoastalLowland,
+    /// Derived from IncisedGorge/ValleyFloor family + high elevation.
-    /// Island context — hub-and-spoke; perimeter access priority.
+    Alpine = 14,
-    Island,
+    /// Volcanic — lava field / shield slope; requires TectonicClass::Volcanic.
-    /// Canyon floor — ribbon or hub-and-spoke only.
+    Volcanic = 15,
-    Canyon,
+    /// Wetland (sub-classification): low-gradient, saturated or seasonally flooded.
-    /// Unknown / unclassified — fallback to AlluvialPlain behaviour.
+    /// Derived from AlluvialPlain/Delta family + low slope + high moisture.
-    Unknown,
+    Wetland = 16,
 }
 
 /// Built-form archetype derived from a settlement's dominant commodity (D-233).