docs: TCRV section entry + TerrainCurve config note + 0_height snapshot (terrain-water task 05)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Core/Scripts/BLUEPRINT_FORMAT.md

@@ -55,6 +55,7 @@ Every section: `[u32 tag][u64 payload-length in bytes][payload]`.
 | `HGTS` / `0x53544748` | `MapSize²` × `f32` height, **X outer / Y inner** | Mandatory. The second index is the map's north/south axis; the server consumes it as world **Z**. (This axis convention was never written down for v1 — it is now normative.) Length must equal `4·MapSize²`. |
 | `BIOM` / `0x4D4F4942` | `MapSize²` × `u8` biome ordinal, same pixel order | Mandatory. Ordinals from `Enums.cs::Biome` — **append-only, never reorder** (the ordinal IS the wire value). Writer refuses ordinals > 255; reader rejects ordinals ≥ the known biome count (parse-time validation; the palette's runtime Dirt fallback for in-memory values is unchanged). Length must equal `MapSize²`. |
 | `TOWN` / `0x4E574F54` | `i32 count`, then per town: `f32 X` · `f32 Y` · `u8 tier` · `u8 isHighwayNode` (0/1) | Tier ordinals from `Enums.cs::TownTier`, append-only, range-checked on read. The highway-node flag is what the generator's road topology was built from (v1 dropped it); carried and exposed on the parsed blueprint, consumed by nothing server-side yet. |
+| `TCRV` / `0x56524354` | 50 B: `u16 curveVersion` · input knots `f32 t1..t4` · `f32 hmaxCal` · output bands `f32 sea` · `f32 orangeCeil` · `f32 redCeil` · `f32 plateauLo` · `f32 plateauHi` · `f32 peakCap` · `f32 tailSlope` | Optional — present iff the height-redistribution curve shaped this blueprint's `HGTS` (config `TerrainCurve: "v1"`); absent = raw legacy profile. **Metadata only:** exported heights are already curved; nothing re-applies the map. The curve itself lives in `Tools/Scripts/HeightCurve.cs` (calibration provenance in its header + the task-05 report). |
 | `WBID` / `0x44494257` | `MapSize²` × `u16` water-body id, same pixel order as `HGTS` | Optional (absent = no water data, e.g. a legacy re-encode). `0` = no water, `1` = **the** ocean body, `2..N` = lakes. Ids assigned in deterministic scan order (X outer / Y inner, first-encountered pixel), lakes labeled with the **same 4-connectivity as `CalculateTrueOcean`**. Membership is exactly the generator's water classification — the biome grid's Ocean/Lake pixels and this grid's nonzero pixels are the same set **by construction** (shared predicates). Length must equal `2·MapSize²`. |
 | `WBTB` / `0x42544257` | `i32 count`, then per body (20 B): `u16 id` · `u8 type` (0 ocean, 1 lake) · `u8 salinity` (0 fresh, 1 salt) · `f32 surfaceLevel` · `i32 pixelCount` · `f32 centroidX` · `f32 centroidY` | Optional, paired with `WBID`. **`surfaceLevel` is a documented TRANSITIONAL rule:** one flat level per body — `GetSeaLevel` at the body's pixel centroid (ocean: at the map centre) under the still-live latitude field; superseded by the flat-scalar sea model (minted, lands with the coast change set). The field's per-pixel slope is deliberately NOT baked into any section. **Salinity is a provisional default** (ocean salt, lake fresh) — a placeholder for the future fresh/salt irrigation mechanic, not a mechanic. |
 | `WSRF` / `0x46525357` | `MapSize²` × `u16` quantized water-surface elevation, same pixel order | Optional, paired with `WBID`. `0` is the reserved **no-water sentinel**; a real level `L` (raw height units) encodes as `1 + round(L × 32768)` so it can never encode to 0; decode `(q − 1)/32768` (`BlueprintFormat.EncodeWaterLevel`/`DecodeWaterLevel`). Covers `[0 … ~1.99997]` raw at `1/32768` raw ≈ **7.7 mm** of world height (1 raw = 251 m) — far finer than the 1 m voxel. Nonzero exactly where `WBID` is nonzero; the value is the pixel's body level. |
@@ -105,6 +106,11 @@ body).
   which model produced it (the `WBTB` levels are the observable).
 - **`SkipRoads`** (bool, default false) — exports with present-but-empty road sections (see the
   road-section table note).
+- **`TerrainCurve`** (`"v1"` | `"off"`, default `"v1"`) — whether the height-redistribution curve
+  (storm ladder: 75 % orange coverage, 50 m plateau, 220 m peaks) shapes `HGTS`. Biome/water
+  classification is curve-invariant by construction (it classifies the retained uncurved
+  heights); town positions and everything 3D follow the curved terrain. When on, `TCRV` records
+  the effective parameters.
 
 ### Deliberately NOT a section: basins (`BSIN`)
 

Tools/Scripts/README.md

@@ -11,6 +11,11 @@ Generates the entire 2D blueprint. Roughly in order:
 2. **Topography** — FastNoiseLite base height plus a mountain spine, minus a squircle distance
    falloff, giving a guaranteed island. Noise frequency is divided by `scaleFactor`
    (`MapSize / 1024f`) so terrain features stay the same real-world size at any map profile.
+   When `TerrainCurve: "v1"` (the default), the calibrated height-redistribution curve
+   (`HeightCurve.cs` — flat farmable lowlands, 50 m plateau shelf, 220 m peak cap) reshapes
+   above-sea terrain after noise/falloff/Trench and before the crater carve; biome
+   classification reads a retained uncurved map, so biomes are identical either way. Drops the
+   `0_height` hillshade snapshot (hypsometric bands × NW hillshade) in both modes.
 3. **Sea level and water** — sea level per the configured model (`SeaLevelModel`: `"flat"` scalar
    — the default, `SeaLevelValue` 0.15 — or the legacy `"field"` latitude Lerp); flood fill
    separates true ocean from inland lakes; a mainland fill guarantees one contiguous landmass.
@@ -65,9 +70,10 @@ Road colours on the snapshot, useful for identifying a road: **red** = Highway,
 
 ### Outputs
 `MapData_Seed_<seed>.dat` (v2), `MapData_Seed_<seed>_v1.dat` (legacy dual-write), and the staged
-snapshots `Map_Seed_<seed>_{0_water,1_biomes,2_towns,3_roads}.png`, all to `user://`. (`0_water`
-is painted from the water stage's own outputs — ocean deep blue, lakes lighter blue, land neutral;
-`3_roads` is absent on a SkipRoads run.)
+snapshots `Map_Seed_<seed>_{0_height,0_water,1_biomes,2_towns,3_roads}.png`, all to `user://`.
+(`0_height` is the hypsometric hillshade of the curved terrain; `0_water` is painted from the
+water stage's own outputs — ocean deep blue, lakes lighter blue, land neutral; `3_roads` is
+absent on a SkipRoads run.)
 
 ## `RoundTripHarness.cs`