fix(simulation): pin SeedDomain::VoxelRelief discriminant + record T-1081 review notes

T-1081 review (Hoshe + Tyre): the seed_domain_discriminants_are_pinned test (the
D-224 guard that fails CI if a variant is renumbered — which would silently re-roll
every world's relief field) did not pin the new VoxelRelief = 11. Add the assertion.

Also fold Tyre's two Q-123 calibration notes into item 4: (i) sanity-check the
slope_q*3 + elev_q envelope on a synthetic high-slope body (both terms cap at 100);
(ii) the relief transect is a single diagonal slice (fine for isotropic fBm, revisit
if an anisotropic ridge field is added).

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

governance/questions/architecture.md

@@ -477,7 +477,7 @@ Technical foundation questions: engine, protocols, data structures, performance,
   1. **Sampling power** — probes per body, number of bodies, number of seeds that constitute "anywhere" (enough that one lucky/unlucky draw is not decisive).
   2. **Non-stationarity** — the similarity metric for "two same-class km² differ" (histogram distance / feature-vector cosine) and the *minimum* dissimilarity that counts as non-repeating; plus a tile-period autocorrelation ceiling (the Netherlands "no two km² alike" rule, made numeric).
   3. **Intra-class variety** — minimum distinct micro-features per sampled patch (K), per terrain class (T-1084).
-  4. **Relief floor** — minimum relief variance, *conditioned on the macro terrain's expectation* (a plain's floor ≠ a montane floor) (T-1081). *(T-1081 landed the metric — `contrast.voxel_relief_m`, mean within-district elevation range over a 2 km transect — with a provisional `≥ 8 m` threshold and a provisional `VOXEL_RELIEF_SPAN_M = 300`; calibrate both, and make the floor macro-conditioned rather than a single global number. Also pending: the **absolute** elevation span is still the compressed `elev_q/N` base — a per-body hypsometric model would set true relief ceilings.)*
+  4. **Relief floor** — minimum relief variance, *conditioned on the macro terrain's expectation* (a plain's floor ≠ a montane floor) (T-1081). *(T-1081 landed the metric — `contrast.voxel_relief_m`, mean within-district elevation range over a 2 km transect — with a provisional `≥ 8 m` threshold and a provisional `VOXEL_RELIEF_SPAN_M = 300`; calibrate both, and make the floor macro-conditioned rather than a single global number. Also pending: the **absolute** elevation span is still the compressed `elev_q/N` base — a per-body hypsometric model would set true relief ceilings. T-1081 review notes to fold in: (i) sanity-check the `slope_q*3 + elev_q` envelope on a **synthetic high-slope body** — both terms saturate the same 0–100 cap, so slope's 3× weight contributes little once elev_q is already high (the tectonic-class ridge-sharpening refinement would address this); (ii) the relief transect samples a single **diagonal** slice — fine for the current isotropic fBm, but revisit if an anisotropic/ridge-aligned field is added.)*
   5. **Coherence** — the vegetation ↔ (moisture / water-distance / slope / aspect) correlation floor; the water-zone-renders-wet check (T-1082); the allowed "impossible combo" set (should be empty). *(T-1082 review note: the current 50% "water renders wet" floor is weak for ocean-dominant bodies — calibrate it **per zone**: post-T-1082 an `OpenOcean` district should render wet ~100% (Dry is impossible), while a mixed coastal district may legitimately read partial.)* Also calibrate the **vegetation-present** denominator: dividing by *all* sampled districts (incl. water) makes the criterion structurally unreachable for a 2/3-ocean world — it should be **land-relative** (exclude water-body districts).
   6. **Climate-appropriateness** — how "*structured-sparse* passes / *blank* fails" is measured on cold/arid bodies, so a frozen world is not failed for being legitimately sparse.
   7. **Pass budget + ratchet** — the % of land probes that must pass to ship (budgeted), and the trigger to ratchet advisory → strict (hard push-gate block).

server/src/seed.rs

@@ -274,6 +274,7 @@ mod tests {
         assert_eq!(SeedDomain::ChunkContext as u64, 8);
         assert_eq!(SeedDomain::Voxel as u64, 9);
         assert_eq!(SeedDomain::Cover as u64, 10);
+        assert_eq!(SeedDomain::VoxelRelief as u64, 11);
     }
 
     #[test]