feedback7 R22-HUD: the cached-atlas refreshes of a crowded battle take their turns from this frame's update order, not random phases — each frame refreshes ⌊n/k⌋ or ⌈n/k⌉ of n units (step 1 of GitHub #327, PR #334 by @Cloudnyco); golden: unchanged

Applied unchanged after review (Grok static review: MERGE; the diff read in full: no network, no dependency).
UnitView._updateImpostor refreshed a unit when (frame + phase) % interval === 0 with a random phase per unit, so the
refreshes of a frame were binomial: reproduced on the parent with 7 pen figures at interval 3 — 5 1 1 5 1 1 … and
2 4 1 2 4 1 … refreshes per frame instead of 2 / 3. Now render/app.js hands every impostor unit the next slot of the frame
(ctx.impostorSlot, a counter reset in frameBody), the unit refreshes when (frame + slot) % interval === 0, and a unit
whose slot keeps moving with the frame (the units before it culled on and off in step) is still refreshed after 2
intervals (imp.last); a context without slots keeps the random phase. Each unit's rate and the total work are unchanged;
no sim or pixel-as-state change.
Step 2 of #327 (a time budget by priority) is not part of this and still needs a decision.

- Tests: test/render/unitview.test.js 'impostor refresh slots' (3: slots in update order — fails on the parent, the
  starvation cap, the no-slots context); unit view / render suites unchanged.
- Docs: design/client.md. Golden: unchanged (client only).

docs/design/client.md

@@ -32,7 +32,7 @@ view.resize() ; view.destroy()
 
 `createFieldView(host, { …, signal })` takes an `AbortSignal` (0.2.2, GitHub PR #302 by @siruimei07): an abort during the build — the Pixi load, the manifest, the fonts, the board art and the 3D board waits — destroys what the attempt made (the canvas, the ticker, the listeners, the observers) and rejects, a failure while it is built releases the same partial resources, and `view.destroy()` is idempotent. `ui/fieldHost.js mountFieldView(host, { signal })` aborts that signal when the engine fails, times out (12 s) or the owner unmounts, disposes a view a factory returns after that, and never clears the other children of `host` — the simplified view and a newer mount share it.
 
-Visuals: oblique perspective board (tilted ~30°, trapezoid tiles), raised highland blocks with side faces, road/floor/forbidden styles per research 07 §7, pulsing red gates, blue objective, dashed hand pads. Units: Spine (Front/Back rule, feet anchored — flying units hover `FLY_HOVER` 1.3 tiles up, the client's 0.35 in character space, research 12, §25.13.5 — an enemy flyer from the road whatever tile it crosses (GitHub #277) —, shadow sprite on the ground), elite gold outline glow, tier chip, HP bar (green ally / red enemy), SP bar (skill ready glow; while an ammo skill runs it is the magazine instead — a yellow cell per round, emptying from the right, `b.snap ammo`, and the skill draws no standing aura, UnitInfo `ammoSkill`), 斩业星熊's 我执 pool as a red bar over her drained HP bar (`b.snap neg`), 伺夜's 狼群 count as a row of diamonds under the bars, the lit ones the 狼影 left (`b.snap wolves`; 0.2.2, GitHub PR #303 / #378 / #383), status icons, the element gauge row under the bars — icon + white bar of the remaining 元素值, element-coloured refill during a 爆发冷却 (§18.3, §20.8); enemies drawn × their official prefab factor (enemies.json `modelScale`, §20.4); an enemy's mode — the `form` of a sim fx (`shared/protocol.js fxForm`), or UnitInfo `form` for a view built later through `render/app/info.js renderInfo` — switches clip sets (`render/units.js FORMS`: 掠海漂移体 crawl, 暴鸰 bombed, 转译基底's forms, the 逐火 embers, the leaders' 重生, 守墓石像, the 孤岛风云 prisoners' warning and 解放; closing clips timed from the fx `dur`), a one-off cast (`PROJ[kind].once`) plays once, and a local-only model's web alias is tinted (`ALIAS_TINT`: 灼热 / 炽焰源石虫, §21.14); damage numbers (phys orange-white, arts purple, true white, heal green); projectiles drawn per kind, hit sparks and melee slashes, skill activation bursts and auras (§17.3); death fade for enemies, summons and devices — a knocked-out operator stays on its tile in its held Die pose under a redeploy ring (§18.3); leak flash at the objective. Fallback when Spine missing/failed: avatar in a rarity-coloured diamond with bob/lunge tweens — a failed or timed-out model is loaded again (bounded), and a view re-resolves its model and avatar when the asset manifest arrives late or the tab is shown again (§21.27). 60 fps target with ≤ 120 units. Picking (which unit a press / hover / dropped item is on) and the drag target follow one rule, `render/pick.js` — the tile under the pointer (§18.1); the Spine store never hands out a skeleton whose unload is in flight (§17.1).
+Visuals: oblique perspective board (tilted ~30°, trapezoid tiles), raised highland blocks with side faces, road/floor/forbidden styles per research 07 §7, pulsing red gates, blue objective, dashed hand pads. Units: Spine (Front/Back rule, feet anchored — flying units hover `FLY_HOVER` 1.3 tiles up, the client's 0.35 in character space, research 12, §25.13.5 — an enemy flyer from the road whatever tile it crosses (GitHub #277) —, shadow sprite on the ground), elite gold outline glow, tier chip, HP bar (green ally / red enemy), SP bar (skill ready glow; while an ammo skill runs it is the magazine instead — a yellow cell per round, emptying from the right, `b.snap ammo`, and the skill draws no standing aura, UnitInfo `ammoSkill`), 斩业星熊's 我执 pool as a red bar over her drained HP bar (`b.snap neg`), 伺夜's 狼群 count as a row of diamonds under the bars, the lit ones the 狼影 left (`b.snap wolves`; 0.2.2, GitHub PR #303 / #378 / #383), status icons, the element gauge row under the bars — icon + white bar of the remaining 元素值, element-coloured refill during a 爆发冷却 (§18.3, §20.8); enemies drawn × their official prefab factor (enemies.json `modelScale`, §20.4); an enemy's mode — the `form` of a sim fx (`shared/protocol.js fxForm`), or UnitInfo `form` for a view built later through `render/app/info.js renderInfo` — switches clip sets (`render/units.js FORMS`: 掠海漂移体 crawl, 暴鸰 bombed, 转译基底's forms, the 逐火 embers, the leaders' 重生, 守墓石像, the 孤岛风云 prisoners' warning and 解放; closing clips timed from the fx `dur`), a one-off cast (`PROJ[kind].once`) plays once, and a local-only model's web alias is tinted (`ALIAS_TINT`: 灼热 / 炽焰源石虫, §21.14); damage numbers (phys orange-white, arts purple, true white, heal green); projectiles drawn per kind, hit sparks and melee slashes, skill activation bursts and auras (§17.3); death fade for enemies, summons and devices — a knocked-out operator stays on its tile in its held Die pose under a redeploy ring (§18.3); leak flash at the objective. Fallback when Spine missing/failed: avatar in a rarity-coloured diamond with bob/lunge tweens — a failed or timed-out model is loaded again (bounded), and a view re-resolves its model and avatar when the asset manifest arrives late or the tab is shown again (§21.27). 60 fps target with ≤ 120 units (a crowd draws its Spine units through the cached atlas, `render/impostor.js`, each refreshed every k-th frame: the refresh turns follow this frame's update order — `ctx.impostorSlot()`, a counter reset at the start of every frame — so a frame refreshes ⌊n/k⌋ or ⌈n/k⌉ of n units instead of whatever random per-unit phases gave, and a unit not refreshed for 2k frames is refreshed regardless; GitHub PR #334 by @Cloudnyco, issue #327 step 1 — its step 2, a time budget by priority, is not done). Picking (which unit a press / hover / dropped item is on) and the drag target follow one rule, `render/pick.js` — the tile under the pointer (§18.1); the Spine store never hands out a skeleton whose unload is in flight (§17.1).
 
 ---