Bug A (zoom reselection dead): select_rung() redesigned from the two-gate
split to a unified per-rung coverage-ceiling walk (MAX_COVERAGE_M,
finest-first) — which also restores District as a reachable rung
(33-131km extent band; the two-gate model had made it structurally
unreachable). Plus the THIRD instance of the PR #191 C1 clamp-mirror bug
class: _maybe_reselect_rung fed the old rung's _held_n raw into the new
rung's request — the server clamped, the held value didn't, every
cross-rung response stale-dropped. Re-clamped at the boundary; the
leaving_tile_mode flag also fixes a stale request-granularity edge case.
Bug B (orbital = whole body): genuine tile-set model. compute_tile_grid
composes ceil-divided Region-tile centers (canonicalized column wrap,
row clamp, Dictionary-set dedup; Lendel = 3x2 = 6 tiles);
AtlasWindowTileSet owns one AtlasWindowRequest per tile (reusing all
tested request/cache/debounce machinery), fans responses out, per-tile
tile_ready — genuinely progressive; the overlay draws arrived tiles as a
mosaic under the one view transform. enter_orbital branches to tile mode
when >1 tile; single-window path unchanged below the coverage ceiling.
E/W wrap at tile seams live-confirmed (col -6400 wraps to 12739). Pole-
row dedup verified correct but flagged honestly as currently-unreachable
defensive logic (no real radius triggers row collision).
All fixes + fallout verified via revert/confirm-fails/restore. Targeted
suites 256/256; gdlint clean; new 20-test tile-set suite.