docs(meta): D-226 T-1124 amendment — PR #185 Troblum findings (windowed-family ceiling, queue-based serving, comment reconciliation)

All five findings applied, none touching the option-(c) carrier choice:
(1) SS2 gains a binding windowed-family ceiling — exactly ONE
windowed-query field; a second windowed query is a dedicated response
message by rule (two concurrent windowed payloads would need the
per-field request-correlation that IS the tagged framing — that is the
trigger to build it); symmetric with the request side's five-hard cap.
(2) SS1 gains a binding serving model — window derives ride the same
Rayon queue + Pending pattern as whole-body cache misses, never inline
in the PreInput drain (which the codebase deliberately keeps expensive
work off); per-connection coalescing recommended; SS4's 7/29ms figures
reframed as worker latency, not tick-thread cost. (3) The
layer_proxy.rs growth-ceiling comment (comment-only diff) now records
the T-1124 ruling as RESOLVED — scoped to the dense whole-body family,
district_window outside it, second windowed field = dedicated-message
migration — instead of deferring to an open design question. (4) SS2
documents that body scoping rides the enclosing AtlasLayerResponse
envelope (cache key body_id+center+n; echo disambiguates within-body).
(5) SS5 entry clarified: zoom threshold alone triggers the swap
(works over open ocean), first window centers on the pan-center's
derived DistrictPos; downstream settlement-anchoring phrasing
reconciled.

pql decisions validate clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/src/atlas/layer_proxy.rs

@@ -75,12 +75,27 @@ pub struct DistrictGridLayer {
 /// T-1119), or a non-ready status.
 ///
 /// Growth ceiling (governance-bounded): the one-`Option`-field-per-layer
-/// pattern tops out at six fields — D-226's 2026-07-13 amendment (d) rules
-/// out any L5/tile Atlas layer ever, and `quarter_footprints` below is the
-/// last candidate the 2026-07-16 T-1112 amendment named. **The budget is now
-/// consumed** — a seventh field is not a naming exercise like the six before
-/// it; what (if anything) carries a future generation-layer addition is a
-/// T-1124 design-pass question, not something to resolve here.
+/// pattern tops out at six fields for the **dense whole-body layer family**
+/// (`district_grid`, `road_graph`, `settlements`, `region_grid`,
+/// `quarter_footprints` — each a compute-once, cache-per-body snapshot) —
+/// D-226's 2026-07-13 amendment (d) rules out any L5/tile Atlas layer ever,
+/// and `quarter_footprints` below is the last candidate the 2026-07-16 T-1112
+/// amendment named. **That budget is now consumed:** a seventh *whole-body*
+/// field is not a naming exercise like the six before it — a future
+/// generation-layer addition needs its own governance, not a drive-by field.
+///
+/// The D-226 T-1124 amendment (2026-07-18) RESOLVED what carries the next
+/// addition, and it is NOT this family: a **windowed viewport query** is a
+/// categorically different payload (keyed on the *request* `(body, center, n)`,
+/// re-fetched per pan, not a per-body snapshot). T-1124 specifies a
+/// `district_window: Option<DistrictWindowLayer>` field (wiring is a follow-up
+/// ticket, T-1137 — not yet added here) that rides on `AtlasLayerResponse` but
+/// is explicitly OUTSIDE the whole-body family and does not count against this
+/// six-field ceiling (D-226 T-1124 §2). The windowed family has its own hard
+/// cap: exactly ONE windowed-query field; a second windowed query (a second
+/// viewport, a windowed chunk-preview) is a dedicated response message by rule,
+/// not a second `Option` here (D-226 T-1124 §2, symmetric with the
+/// request-side five-shape demux ceiling in `bridge/mod.rs`).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AtlasLayerResponse {
     pub body_id: String,