feat(simulation): relief_q — a local relief signal the deep rungs can resolve (T-1213)

The District and Quarter rungs rendered as flat colour, and the cause was not
the biome work everyone assumed. Measured on Ferrath through the production
canvas builder: at District the mean |elev_q delta| between neighbouring
gridunits is 0.02, and NOT ONE PAIR in a 1290x540 frame differs by 2.

elev_q spans 0-100 across the body's whole 8 km elevation range, so ONE STEP IS
80 METRES. A District canvas covers 2,048 m of ground, where the rolling relief
a walker navigates by is metres to tens of metres -- a fraction of a single
step. The sub-district detail IS generated (invent_primitives' scatter and
relief bands compute it) and then rounded away. Confirmed by running the
diagnostic with the octave cutoff disabled: still 0.02.

relief_q carries that same invented fine component against a scale chosen to
resolve it: 0-100 about a flat 50, RELIEF_FULL_SCALE_M = 400 m either side, so
8 m per step -- ten times finer than elev_q. elev_q keeps its body-absolute
meaning and the Atlas legend stays true.

Measured effect, elev_q vs relief_q (distinct values / mean 4-cell delta):

  Region     49 / 2.38   ->   101 / 21.86
  District   10 / 0.08   ->    35 / 0.35
  Quarter     8 / 0.02   ->    19 / 0.06

FIXED metre scale, never per-canvas normalization: the value for a piece of
ground must not depend on what else is in frame, or the same hillside changes
tone as the viewer pans. And it excludes elev_pct deliberately -- this is the
departure from the surrounding land, not height above sea level; including the
base would re-introduce the body-scale dominance that makes elev_q unusable
down here.

50 at the orbital rungs, which skip invent_primitives by design. Nothing is
lost: Global and Region still have varied elev_q (101 and 49 distinct values),
and the client takes whichever field carries signal via a max, with no
rung-name branching.

The client's ruggedness driver changes with it. It was an elev_q GRADIENT,
which cannot work across rungs -- the same 4-cell delta reads 21.86 at Region
and 0.08 at District, so any single full-scale constant either saturates one or
vanishes on the other. relief_q states relief outright, so |relief_q - 50| is
the answer directly and a fixed metre scale is immune to that by construction.

An absent plane reads FLAT, not zero -- 0 on this field means maximum relief
BELOW flat, so a payload without it would have stippled the entire map. That is
reachable: the field is #[serde(default)] so old-shape payloads decode. Two
colorize tests whose fixtures predate the plane caught it.

2004 server tests, 1838 client tests, 0 failed. clippy clean.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.pql/changelog/ticket_idmap/2026-08.sql

@@ -1 +1,2 @@
 INSERT INTO ticket_idmap (record_id, ticket_id, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('06FXF1VDVQDQ8EFGTXX787M90R', 'T-1239', '2026-08-06 14:43:24.767', '2026-08-06 14:43:24.767', NULL, 'ae5ccb58f885727882f56ce2a32c91e3', 2) ON CONFLICT(record_id) DO UPDATE SET ticket_id=excluded.ticket_id, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > ticket_idmap.updated_at OR (excluded.updated_at = ticket_idmap.updated_at AND excluded.hash > ticket_idmap.hash);
+INSERT INTO ticket_idmap (record_id, ticket_id, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('06FXRSY7QWD8J5X6G1N86WMKEC', 'T-1240', '2026-08-07 13:26:56.708', '2026-08-07 13:26:56.708', NULL, 'dc79a976524b951a73f05532772ef86a', 2) ON CONFLICT(record_id) DO UPDATE SET ticket_id=excluded.ticket_id, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > ticket_idmap.updated_at OR (excluded.updated_at = ticket_idmap.updated_at AND excluded.hash > ticket_idmap.hash);

.pql/changelog/tickets/2026-08.sql

@@ -166,3 +166,4 @@ rivers vanish on descent. That is tracked separately as T-1239 and is NOT this
 ticket''s scope, but it will be visible in the same captures, so do not mistake it
 for a failure of the un-summarisation work.', 'in_progress', 'high', NULL, NULL, 'D-258', '2026-07-26 21:54:15.245', '2026-08-07 11:36:20.464', NULL, '94ccf78431914ea836ba5d59170a3395', 2) ON CONFLICT(record_id) DO UPDATE SET type=excluded.type, parent_record_id=excluded.parent_record_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);
 INSERT INTO tickets (record_id, type, parent_record_id, title, description, status, priority, assigned_to, team, decision_ref, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('06FSJWSX11WV3C1XXZEV88Q3P0', 'task', '06FB0TNSRZXCHGS16BFHSSGSV4', 'Biome/relief stipple-density layer on the terrain build (RimWorld technique 4)', 'Follow-up from T-1175''s assess-only item (2026-07-25, stig''s write-up): a stipple/texture-density layer carrying hills/mountains/forest on top of hue, driven by the already-wire-carried vegetation and elev_q L8 planes — presentation-only, D-255(e)-legal (texture-space dithering of already-derived per-cell values, deterministically seeded per cell coordinate + value so it is stable across cache hit/miss; never invents samples between server cells). Would live as a post-process in step_canvas_terrain_layer.gd::rebuild_from_canvas()''s Image.set_pixel build. Design questions to settle at pickup: (a) stipple dots inline in the existing per-cell loop (cheap, same O(wxh) pass) vs a second overlay pass (simpler code, doubles pixel-touch cost); (b) density from vegetation class directly vs a combination with elev_q — relief hachures and forest texture are two different visual grammars in the RimWorld reference, not one slider; (c) own legend toggle (TMP/MST/VEG overlay-bar pattern) vs always-on like the elevation lightness modifier. Reference: docs/design/references/rimworld-world-map-fluency.jpg. Related: T-1175, T-1162 (vegetation patchiness fields), D-255(e).', 'in_progress', 'low', NULL, 'client', NULL, '2026-07-25 13:24:54.152', '2026-08-07 12:44:21.620', NULL, 'c1560b624bd9a9d79fe919f282620f22', 2) ON CONFLICT(record_id) DO UPDATE SET type=excluded.type, parent_record_id=excluded.parent_record_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);
+INSERT INTO tickets (record_id, type, parent_record_id, title, description, status, priority, assigned_to, team, decision_ref, created_at, updated_at, deleted_at, hash, canonical_version) VALUES ('06FXRSY7QWD8J5X6G1N86WMKEC', 'task', '06FB0TNSRZXCHGS16BFHSSGSV4', 'MIN_WL_BANDS_M octave cutoffs are pre-extent-inversion (stale, currently inert)', 'Found during T-1213 (2026-08-07). MIN_WL_BANDS_M (layer_proxy.rs) is built from 2*DISTRICT_M (4,096 m) and 2*QUARTER_M (1,024 m) -- Nyquist for a sample spacing equal to the rung''s CELL SIZE. That was correct while a rung fixed SPACING; after D-255''s extent inversion a rung fixes EXTENT and District''s spacing is 2048/540 = 3.8 m, so its true Nyquist floor is ~7.6 m. The bands are off by roughly the canvas cell count (~540x). This is the same class of defect as the Global 2x1 wire-extent sentinel the D-258 amendment documents: a constant that was correct under the pre-inversion model and silently outlived it. The code even states the consequence as though intended -- district_profile.rs''s comment reads ''At District''s real Nyquist floor (4,096 m) every VOXEL_OCTAVE_WAVELENGTHS_M entry is truncated, so relief is always exactly 0.0 there''. IMPORTANT SCOPE NOTE, verified before filing: this is currently INERT for the step canvas. step_canvas_viewer._fire_request() calls request_now(body, rung, center, extent) with no min_wl_m, so it defaults to 0, and quantize_min_wl_m(0) returns 0 (the leading sentinel band) -- no truncation happens on the served path. It therefore only affects the legacy layer_proxy district-window consumer. It is NOT the cause of the flat District/Quarter rungs; that is elev_q''s 80 m quantisation (0-100 across MAX_REGION_ELEVATION_KM = 8.0 km), measured at d1 mean 0.02 with the cutoff already disabled. Fix: derive the cutoff from the resolved canvas spacing rather than the rung cell size. Check the layer_proxy consumer''s expectations first -- MIN_WL_BANDS_M is shared, carries a const assert tying band 4 to OCTAVE_WAVELENGTHS_M[3], and is part of the cache key, so a change there is not local.', 'backlog', 'medium', NULL, 'server', 'D-255', '2026-08-07 13:26:56.703', '2026-08-07 13:26:56.703', NULL, '45cb7553effbe05042fe7f3eb09e6483', 2) ON CONFLICT(record_id) DO UPDATE SET type=excluded.type, parent_record_id=excluded.parent_record_id, title=excluded.title, description=excluded.description, status=excluded.status, priority=excluded.priority, assigned_to=excluded.assigned_to, team=excluded.team, decision_ref=excluded.decision_ref, updated_at=excluded.updated_at, deleted_at=excluded.deleted_at, hash=excluded.hash, canonical_version=excluded.canonical_version WHERE excluded.updated_at > tickets.updated_at OR (excluded.updated_at = tickets.updated_at AND excluded.hash > tickets.hash);