docs(meta): T-1143 rulings — D-226(d) floor opened, progressive-tiling planetary carrier, continuous seam zoom; implementation chain T-1149..T-1155

Jeroen's three rulings on the zoom-ladder design pass, recorded as a
D-226 amendment: (1) 'we set a new BHAG so old restrictions are up for
debate' — the item-(d) ceiling opens for the Atlas windowed viewport
(below-quarter rungs gated on the T-1154 measurement pass; chunk/tile
still never a whole-body planetary layer); (2) planetary rung ships as
progressive capped-density tiling on the generalized district_window
carrier; (3) planetary->regional entry becomes continuous cursor-anchored
zoom with full-zoom-out resetting to the canonical orbital frame (D-013
zoom-owns-descent restored; click-through cut superseded).

Design doc stamped with the resolved rulings. T-1143 closed. Implementation
chain: T-1149 (derive_at_metres + octave cutoff) -> T-1150 (granularity
carrier + aliasing test) / T-1151 (window par_iter) -> T-1152 (derived
planetary rung) / T-1153 (client continuous ladder) -> T-1155 (smoothing
retirement); T-1154 below-quarter measurement gate.

governance/decisions/architecture.md

@@ -1668,6 +1668,8 @@ Technical foundation decisions that constrain implementation: engine, client-ser
   **Amended 2026-07-21 (T-1124 §5 entry revision — Jeroen, first companion hands-on):** the regional-map **entry mechanic changes from zoom-threshold LOD swap to explicit click-through**. Jeroen's ruling after using `make atlas`: the planetary pixel-scaling pan/zoom "is only messing with the pixels of the map and the interaction is weird" — (a) the **planetary heightmap view becomes FIXED** (no drag-pan / wheel-zoom of the planetary canvas; the current pan/zoom ships until T-1138 replaces it, then is removed *in the same change* as the replacement so close inspection is never stranded); (b) **entry is a click-through**: hovering the planetary heightmap shows a **rectangle cursor** representing the regional-mode bounds, and clicking descends into the regional map centered on the click point's derived `DistrictPos` — §5's float-on-center/first-window rules carry over with "pan center" read as "click point". `DISTRICT_WINDOW_MIN_ZOOM` is retired before ever being built (the T-1138 zoom-headroom note is moot); the §5 cross-reference reading of D-013 ("the zoom gesture owns spatial descent") is superseded **for this seam only** — click owns descent. Everything *inside* the regional mode stands unchanged (§4 pan-only refetch, debounce, float-on-center, D-227 cache, border-fade). A **morphing transition** between map modes is explicitly deferred (Jeroen: nice, too ambitious for now) — the descent may cut. **Open at T-1138:** the rectangle cursor is an affordance, not to scale — an n=64 window (~131 km) is a few pixels on a planetary canvas; the screen design must resolve the honest representation (rectangle at true extent with a zoom-in cut on click, or a not-to-scale reticle with the real extent labeled beside it) without implying the regional view covers more planet than it does.
 
   **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.
 - **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.