fix(simulation): PR #191 review round — n-clamp mirror, min_wl band quantization, coalescing coverage, fixture consumer

All seven Hoshe/Tyre findings addressed, none retracted:
- n-clamp/echo/staleness triangle (Tyre C1): client _clamp_window_n_mirror
  (bit-for-bit twin of the server clamp, canonicalize_district_center
  precedent) applied before _n is stored/sent; server test pins the
  quarter n=32 -> echo 16 contract.
- min_wl band quantization (Hoshe 1/Tyre C3): quantize_min_wl_m snaps to
  MIN_WL_BANDS_M {0, 32768, 16384, 8192, 4096} before cache key and echo
  (design doc §5's unbounded-key fix), reusing the one true
  OCTAVE_WAVELENGTHS_M array; docstrings now state the server-quantizes/
  client-sends-raw split; same-band cache-sharing test.
- coalescing granularity axis (Hoshe 2): two tests pin different-
  granularity requests as separate in-flight slots and same-granularity
  coalescing unchanged.
- orphaned fixture (Hoshe 3): test_protocol.gd consumer decodes
  atlas_response_ready_with_window.msgpack through the real IPC path and
  asserts the new fields.
- atlas_window_request coverage (Hoshe 4): new test file — stale-drop on
  granularity mismatch, old-server-shape defaults accepted, clamp mirror
  formula + wiring. First draft's quarter-via-request_now test would have
  passed for the wrong reason (request_now resets granularity by design
  until T-1153) — split into formula pin + reachable-path wiring proof.
- granularity type seam (Tyre C2): field + resolver docstrings state
  finer-only integer multiples with resolve_window_granularity as the
  single widening point; matching contract note added to the D-226
  T-1143-rulings amendment.

cargo --lib 1807/1807; goldens bit-identical; gdlint clean.

governance/decisions/architecture.md

@@ -1669,7 +1669,7 @@ Technical foundation decisions that constrain implementation: engine, client-ser
 
   **Amended 2026-07-21 (T-1145 — Jeroen, second companion hands-on, KALLAST window):** three regional-window presentation fixes, all client-only. **Cover-fit supersedes contain:** `fit_window_view()`'s zoom now derives from the LARGER viewport dimension with no margin factor (`max(viewport.x, viewport.y) / composite_native`, not the old `0.9 * min(...)`), so the square district-window composite fills a wide/tall viewport edge to edge instead of leaving side margins, with the shorter axis' data extending into pan-space (the same "cover" concept as CSS `object-fit: cover`) — the existing §4 pan-edge refetch is unaffected (it keys off the screen-center-to-DistrictPos mapping, which any fit already centers on `_held_center` by construction, so no refetch churn at rest). **WASD + edge-scroll supersedes drag-pan:** LMB-drag panning is removed entirely (Jeroen's ruling — drag conflicts with click semantics for the map objects, e.g. settlements, this window will host later); panning is now held WASD/arrow keys (continuous, frame-rate-independent, `_process`-polled, physical-keycode reads to stay independent of the project's existing `move_north`/etc. gameplay-movement InputMap actions bound to the same keys) plus edge-scrolling (cursor within ~24px of a viewport edge, suppressed over UI and while the OS window lacks focus); wheel zoom is unchanged; pole-wall (§5 amendment above) and east-west wrap (T-1142) semantics are preserved unchanged under the new input source. **Smoothing is an interim presentation, pending T-1143:** the composite renders as an `n`×`n` `Image`/`ImageTexture` (one pixel per district, the identical existing per-cell color pipeline) drawn scaled with linear filtering — the same treatment the planetary heightmap already gets — instead of `n`×`n` flat rects, so GPU bilinear sampling reads as a terrain gradient rather than hard blocks; the original crisp per-cell path survives behind a compile-time const specifically so T-1143's design pass can compare both directly, and this smoothing is **not** T-1143's answer to district-tier legibility, only a stopgap ahead of it.
 
-  **Amended 2026-07-21 (T-1143 design-pass rulings — Jeroen, after the zoom-ladder design pass, `docs/architecture/atlas-zoom-ladder-t1143.md`):** three rulings on the pass's reserved decisions. **(1) The item-(d) ceiling is opened for the Atlas ladder** — Jeroen: *"we set a new BHAG so old restrictions are up for debate."* The D-166 2026-07-21 zoom-ladder condition ("down to tile scale") is read **literally**: the Atlas windowed viewport may descend below quarter (512 m) toward block/tile granularity. This is an explicit ruling, not erosion — exactly the deliberate revisit the T-1112 §2 anti-erosion clause was hardened to force into the open. Item (d)'s substance survives in narrowed form: chunk/tile/voxel output still never appears as a **whole-body planetary map layer**, and the below-quarter rungs are implementation-gated on their own **measurement pass** (costs/wire for block and tile rungs are unmeasured — design pass §2/§7); the harness-verification path for L5 fill remains primary until that pass lands. **(2) Planetary rung wire carrier: progressive capped-density tiling** riding the generalized `district_window` carrier (granularity parameter, §3 of the design pass) — no new dense-raster wire shape, no forced tagged-envelope migration. **(3) The §5 entry click-through cut is superseded by continuous cursor-anchored zoom**: wheel-zoom carries the view from the orbital frame down through regional granularities continuously, anchored at the cursor, **with the condition that a full zoom-out resets to the original canonical planetary frame and location** (the fixed orbital framing is the ladder's top rest state, not a drifted pan state). The click-through descent and rectangle reticle are retired as the *sole* entry (T-1138's shipped mechanic stands until the continuous ladder replaces it in the same change — close inspection is never stranded, same discipline as the §5 fixed-view transition). D-013's "the zoom gesture owns spatial descent" reading is **restored** for this seam.
+  **Amended 2026-07-21 (T-1143 design-pass rulings — Jeroen, after the zoom-ladder design pass, `docs/architecture/atlas-zoom-ladder-t1143.md`):** three rulings on the pass's reserved decisions. **(1) The item-(d) ceiling is opened for the Atlas ladder** — Jeroen: *"we set a new BHAG so old restrictions are up for debate."* The D-166 2026-07-21 zoom-ladder condition ("down to tile scale") is read **literally**: the Atlas windowed viewport may descend below quarter (512 m) toward block/tile granularity. This is an explicit ruling, not erosion — exactly the deliberate revisit the T-1112 §2 anti-erosion clause was hardened to force into the open. Item (d)'s substance survives in narrowed form: chunk/tile/voxel output still never appears as a **whole-body planetary map layer**, and the below-quarter rungs are implementation-gated on their own **measurement pass** (costs/wire for block and tile rungs are unmeasured — design pass §2/§7); the harness-verification path for L5 fill remains primary until that pass lands. **(2) Planetary rung wire carrier: progressive capped-density tiling** riding the generalized `district_window` carrier (granularity parameter, §3 of the design pass) — no new dense-raster wire shape, no forced tagged-envelope migration. **(3) The §5 entry click-through cut is superseded by continuous cursor-anchored zoom**: wheel-zoom carries the view from the orbital frame down through regional granularities continuously, anchored at the cursor, **with the condition that a full zoom-out resets to the original canonical planetary frame and location** (the fixed orbital framing is the ladder's top rest state, not a drifted pan state). The click-through descent and rectangle reticle are retired as the *sole* entry (T-1138's shipped mechanic stands until the continuous ladder replaces it in the same change — close inspection is never stranded, same discipline as the §5 fixed-view transition). D-013's "the zoom gesture owns spatial descent" reading is **restored** for this seam. **Wire-contract note (T-1150, PR #191 review — Tyre):** the `window_granularity` field ruling (2) rides on expresses **finer-than-district integer multiples only** (1 = district, 4 = quarter today; each new rung is a deliberate widening of `resolve_window_granularity`'s whitelist — the single widening point; unknown values fall back to district, never trusted from the wire). Coarser-than-district reuse (the region/orbital rungs of ruling (2)'s progressive tiling) requires the design pass's R5 signed/log-scale-or-enum redesign of the field — a new magic value is not the path. Recorded here so the type's limit is contract, not only a design-doc risk row.
 - **Rationale:** Reusing the real UI — rather than a parallel offline renderer or dumped files — means the debug/review surface never diverges from what ships, and a dropped artifact can't go stale. Agent-navigability converts qualitative "does the synthesis look natural?" review from a manual eyeball pass into an automatable sweep that flags the few outliers for a human. The harness rides seams that already exist (`TickRate::Paused`, the paused-allowlist, `gameplay_occluded`, the bridge framing, the `run-visual` capture primitive) — a naming-and-contract exercise, not a new subsystem.
 - **New surface:** server pause-gating (run-conditions on the world phases keyed to a pause command); client `AtlasAgentInterface` (`observe`/`act`, Control-tree walker) + its local transport; the generation overlay rendering + selector + legend; interactive capture wired to `run-visual`.
 - **Implementation:** Phase 4 (epic T-750), built bottom-up — auto-pause substrate, T-969 proxy (D-225), T-960 viewer, agent channel, agent capture. Geography is the first consumer.