docs(decisions): add D-246 micro-habitat mosaic + D-247 native biospheres (amend D-228)

D-246 (architecture): intra-class micro-habitat mosaic — a voxel_mosaic()
sub-chunk noise band modulates the D-228 axes into spatially-coherent,
relief-conditioned micro-habitats; palette keyed on surface-class ×
climate-biome × biosphere-register; five new D-228 axis values front-loaded
for determinism; within-patch believability metric in scope. Governs T-1084.

D-247 (content): habitable Reach worlds were alive before humans — the
settlement timeline forbids terraforming from dead rock. An authored per-world
chirality bit gates whether native life is edible (Compatible) or
inedible-but-inert (Mirror); "safe" and "edible" are decoupled; colonization
is ecological war that grows an Earth-crop footprint outward from settlements.
Grounds D-246's native-vs-introduced register.

D-228 amended: +Vegetation{Meadow,Deadfall,Lichen}, +TerrainMaterial{Hardpan,Scree}.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

governance/decisions/content.md

@@ -621,4 +621,25 @@ How narrative, NPCs, and world content are created: content tiers, NPC generatio
 
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-*47 decisions. Last updated: 2026-04-21 (D-193 Lattice Commission name resolved)*
+### D-247: Native pre-existing biospheres + chirality food-safety bit — why the Reach is breathable, and half of it inedible
+
+- **Date:** 2026-07-02
+- **Decision:** Habitable Reach worlds are **not terraformed from dead rock — they were already alive when humans arrived.** The settlement timeline forbids anything else, and their native biospheres are what make them breathable. A per-world **chirality bit** then decides whether that native life is food.
+  - **The timeline forbids terraforming-from-scratch.** Settlement runs Wave 1 (500–600 y ago) → Wave 5 (0–40 y ago); the whole Reach is ≤ ~600 years old. Canon already prices terraforming *above* that ceiling: Earth spent **800 years** terraforming one of its own worlds (GJ-0); Oshima Prime (GJ-79) holds only a *thin* atmosphere by continuous **terraforming infrastructure** that burns **8% of its working population**, and is framed as a burden and an anomaly. You cannot make a dead world breathable in the settlement window. Therefore **the good worlds were pre-alive** — a native biosphere ran the oxygen. "Implemented atmosphere" is the rare, expensive exception; **native life is the rule.**
+  - **The chirality bit (Mass Effect's levo/dextro), an AUTHORED per-world property.** Each **living** world's biosphere is either **Compatible** ("levo" / Earth-standard handedness) or **Mirror** ("dextro" / opposite handedness). It is **authored, not derived** — the bit follows a world's economic/cultural identity, so a food/whiskey exporter is edible *by construction* and is never left to a coin flip. A rough **50/50 balance is a design target across canon-silent worlds**, not a per-world draw. Homochirality is the gate: our stereospecific enzymes only cleave one handedness.
+    - **Compatible ("levo") → edible.** Native macromolecules share our handedness, so native life is digestible/nutritious and Earth crops interleave with it. Compatibility *permits* biochemical coupling — a Compatible world **can** be authored to host a native pathogen or a binding toxin, and Earth/native ecology can compete — but coupling is **not forced**: most Compatible worlds are benign gardens. **Edibility is guaranteed; hazard is an authored option.**
+    - **Mirror ("dextro") → inedible, and *guaranteed* inert.** Mirror substrates pass through non-nutritively (starve on a full stomach); nothing native can infect or chirally poison you — *ever*. Safe to walk and study, valueless to harvest. The already-canon Solandar case (GJ-827: *"cannot infect humans and humans cannot eat them… available for study without the additional complexity of anyone dying from it"*) and the "no meaningful indigenous hazard" worlds (GJ-524).
+    - **"Safe" ≠ "edible" — they are two independent axes.** *Bio-safe* (nothing hurts you) is broadly true and **guaranteed on Mirror**; *food-safe* (you can eat it) is the **Compatible-only** property. So attractive worlds can be safe in either sense, and they pull **opposite** bits — which is exactly why the bit is authored identity. Worked examples: **Arbour** (GJ-338B, "lovely, by invitation," families *grow their own estate-grade food*) is **Compatible** — a benign edible garden; **Solandar** (GJ-827) is **Mirror-inert** — alien life safe to study precisely *because* nothing can eat or infect anyone (opposite bits, both attractive). And **Keid** (GJ-166A, the Cadwal Conservancy) is **Compatible** too, but preserved for the *inverse* of Arbour's private reason: its **edible** alien biology is an exploitation target, and the Conservancy exists to keep capital from strip-mining it. **A preserve over something *valuable* is the stronger act of conservation** (we fence off rainforests because they are precious, not worthless) — and it fits Keid's canon of exclusivity, scarcity-as-leverage, and Perpetual-family gatekeeping far better than an inert biology would. Two preserve archetypes: *protect-the-inert-for-study* (Solandar) and *protect-the-valuable-from-capital* (Keid).
+  - **The achiral seam (what always works regardless of the bit).** Chirality only governs molecular *recognition*. So **breathe the air, drink the water, mine the ore, burn native wood, build with it** all work on any living world (O₂/N₂/CO₂/H₂O, minerals, combustion, and structure are handedness-independent). Only **eat / metabolize / medicate / infect / chirally-poison** are gated by the bit. This is the seam that makes an inedible world a *setting*, not a prison: native biomass is an **industrial** resource (fuel, timber, feedstock), never a grocery or a pharmacy.
+  - **Colonization is ecological *war*, not terraforming.** Two centuries can't build an atmosphere, but they are ample to **burn back native ecology and hold an Earth-crop perimeter.** So the Earth-chirality footprint is a **spatial field that grows outward from settlements over wave-time**: `P(introduced Earth ecology) ≈ f(distance-to-settlement, settlement_age, economic_tier, arability)`. Wave-1 capitals → broad established farmland; Wave-5 frontier → a thin beachhead in native wilds. Three policy states per locale: **converted** (Earth-managed core), **contested** (naturalized front — escapees vs native reclaiming; abandoned land reverting), **preserved** (native biosphere protected — either *from exploitation* because it is edible/valuable (Keid, GJ-166A, the Cadwal archetype) or *for study* because it is inert (the Solandar xenobotany economy, GJ-827)). Mirror worlds show *sharp two-biosphere fronts*; Compatible worlds show *blended, competing* ecology.
+  - **Code hooks (bounded, verified derivation-safe).** A new body attribute `biosphere_class ∈ {NativeCompatible, NativeMirror, TerraformedSterile, Airless}`, read *once per body*, consumed downstream (food/economy/perception), touching **nothing** in voxel geometry. It is an **authored input, not a derivation** — chirality follows a world's authored economic/cultural identity (Arbour's estate families *grow their own food*; a coin flip could wrongly declare that biology inedible), so it is authored data, never seeded entropy. Home: wiki body frontmatter (where `substrate:` already lives) → a nullable `bodies.biosphere_class` column → the `BodyParams` read set (D-240). Canon-silent bodies take a **principled default inferred from `economic_base_primary` + `planet_class`** (still authored-data logic, not entropy), with explicit per-world overrides where canon speaks (Solandar=Mirror, Keid=Compatible, Oshima=`TerraformedSterile`, Arbour=Compatible). That frontmatter + schema + importer bundle **lands with the Miri continuity pass** (asset-pipeline: schema ships with its source + consumer) — **no column is needed for D-246**, whose native mosaic is chirality-agnostic. Provenance at the tile is a new **orthogonal overlay field** `VoxelColumn.biosphere ∈ {Native, Introduced}` (defaulted `Native`, `#[serde(default)]`), sitting beside `cover` — set `Native` by the wild/natural derivation (all of Phase 4) and `Introduced` by the future managed override, i.e. it is exactly D-228's **wild → economic/managed** precedence read as a label. Every voxel still resolves to a complete D-228 tuple; the bit adds no unset state and no new RNG.
+  - **Scope.** The *biochemistry* is phase-independent canon. The *tile register* is Phase 4 — but only its **native** half exists now (the managed Earth-conversion layer is drawn later by the settlement/economic pass, D-166 outside-in). Food-supply economics is a Phase-2 consumer (already latent — agriculture-as-leverage, frontier net food importers). Foraging futility, predators that gore-but-don't-eat, absent native medicine, and Earth-blight-not-native-plague are **parked gameplay** (T-1036) — flagged, not designed here.
+- **Rationale:** "Implemented" is a false summit for a setting the same way it is for the cascade (cf. [D-245](../decisions/architecture.md#d-245)). The Reach's habitability was scattered across a dozen wiki entries as unexplained flavor ("alien biochemistries, incompatible, inedible, non-infectious — *almost always*"); this record supplies the single mechanism that predicts all of it *and* its exceptions, and turns "can I eat here?" into a legible, generatable world property. The 50/50 chirality boolean (vs a fuzzy "usually incompatible") is chosen because it makes both world-classes common enough to matter and gives the storyteller a hard axis. Native-life-not-terraforming is forced by the timeline math the setting already committed to. Touchstones: Mass Effect (levo/dextro food chirality), Vance's *Cadwal Chronicles* (the Conservancy world → Keid), the Bobiverse (convergent-but-alien niches), Hamilton's Commonwealth (non-animal/mega clades, the Primes), Card's descolada/Lusitania (a biosphere as one linked genetic system).
+- **Affects:** **Wiki continuity pass** (Miri) over the entries that already gesture at this, each assigned a chirality bit consistent with its authored identity — GJ-338B (Arbour — Compatible; estate-food garden), GJ-827 (Solandar — Mirror-inert research preserve), GJ-166A (Keid — Compatible; preserved *because* its edible native biology is an exploitation target — conservation against capital), GJ-524 (Mirror), GJ-684A (native + introduced coexisting), GJ-197 (Earth introductions thrive), GJ-79 (Oshima — `TerraformedSterile`), GJ-124 (Hạ Long — resolve whether its "protein" is native-Compatible harvest or Earth aquaculture). **Schema/code:** authored `bodies.biosphere_class` column + wiki frontmatter (nullable; principled default from `economic_base_primary`+`planet_class`, explicit overrides) — an **input, not a seed derivation** — landing with the continuity pass; `VoxelColumn.biosphere` overlay field. **Economy** (Burnelli): food-supply demand primitive keyed on `biosphere_class`. **[D-246](../decisions/architecture.md#d-246):** its palette register is now grounded as native-mirror-wild vs introduced-Earth-managed.
+- **Cross-reference:** [D-246](../decisions/architecture.md#d-246) (the mosaic register that consumes this — native vs introduced), [D-228](../decisions/architecture.md#d-228) (the wild→managed override stack this labels), [D-227](../decisions/architecture.md#d-227) (derive-don't-store — `biosphere` is a derived overlay), [D-166](../decisions/scope.md#d-166) (outside-in — the settlement pass draws the Earth-conversion layer), [D-188](../decisions/architecture.md#d-188) (`planet_class` — the sibling body attribute), [D-240](../decisions/architecture.md#d-240) (BodyParams read set `biosphere_class` joins), [D-245](../decisions/architecture.md#d-245) (believability — the conversion gradient supplies coherence + non-stationarity for free). Tickets: T-1084 (D-246 mosaic register), T-1079 (epic); a Miri continuity/vocabulary ticket to be filed.
+- **Raised by:** Jeroen — the native-life-not-terraforming premise (two centuries can't terraform but can wage ecological war), the mirror-/counter-chirality DNA-enzyme indigestibility mechanism, the Mass-Effect chirality food-safety boolean (~50/50 target), the authored-input-not-derivation call (Arbour's estate food; Keid = Compatible, preserved against exploitation of edible alien life; "safe" ≠ "edible"), and Keid-as-Cadwal — with Claude (timeline/canon verification, tile-derivation safety check, the wild/managed override mapping, and the consequence analysis), 2026-07-02, during the T-1084 (D-246) refinement conversation. Setting development + wiki continuity owned by **Miri**; food economics by **Burnelli**.
+- **Dissent:** None.
+
+---
+
+*48 decisions. Last updated: 2026-07-02 (D-247 — native pre-existing biospheres: habitable Reach worlds were alive before humans; an **authored** per-world chirality bit (~50/50 target) gates whether native life is edible (Compatible) or inedible-but-inert (Mirror) — "safe" and "edible" are decoupled; colonization is ecological war that grows an Earth-crop footprint outward from settlements; grounds the D-246 mosaic register; Miri + Burnelli own development).*