fix(render): show exact remaining ammunition

Reference: lolink’s numeric ammunition display in https://github.com/Yilegendoflink/garrison-protocol/commit/071ed14aa27d5ebf54e57447c958f2681737403c. This implementation uses the existing PIXI HUD and exact snapshot counts; no fork code is copied.

docs/design/client.md

@@ -40,6 +40,11 @@ Visuals: oblique perspective board (tilted ~30°, trapezoid tiles), raised highl
 
 ## 10. Client UI (screens & components)
 
+Active ammunition skills also show `remaining/capacity` below the segmented skill bar, using the exact `b.snap ammo`
+integers, including extra rounds and refills. The label stays readable when cells are too narrow to separate. It hides
+with the ammunition row, during preparation and after death; elemental gauges sit below it. This is a display-only
+readout, not a change to ammunition consumption or skill duration.
+
 Look & feel: research 06 §11–§12 (near-black green-grey panels, mint `#4ed8af` accents, gold prices, bracket frames, hexagon badges, bond discs, 7-segment countdown). Fonts: Noto Sans SC (Google Fonts with local fallback), Bender/Novecento self-hosted for numerals and Latin micro-labels.
 
 Screens: **Title** (season art backdrop, 开始 → nickname), **Lobby** (独立模拟 / 同盟模拟 → create or join; recent rooms; a 设置 button left of 玩法说明 opens the title screen's settings dialog, GitHub #238), **Room** (4 seats, invite code + copy link, difficulty picker (host), the co-op 「AI 队友最后选择」 switch (host, off by default; read-only for the others), add/remove AI, ready, start; the same 设置 button), **Briefing** (INFO_CHECK: stage, factions, disabled bonds, banned chess, boss silhouette, ready x/4), **Band draft** (grid of 40 bands with icon/name/LP/effect; turn order list; skip; 查看禁用盟约与干员 under the order list opens the briefing's bond rows, legend and banned operators again in a read-only dialog — one component, `ui/matchInfo.js`, §21.28), **Game** (Pixi field + DOM HUD: top bar with round/phase capsule (the kill counter reads 已解决 / the round's own enemies: a leak counts, a split child or summon is in neither number, §14)/LP (live during the own battle, §17.5)/timer/ready, and beside the latency a 观战席 capsule (eye + count, a roster with the host's ✕) while the room has spectators (GitHub #120); bond strip + popups; left team panel with LP/status/emote bubbles, click to watch (a boss round frames the viewer's pair in green, §15); bottom shop bar (level card, 3–5 chess cards — a slot the upgrade just opened is a bare frame until the next refresh, GitHub #332 —, item card, funds, refresh, freeze, collapse; 准备就绪 folds it and cancelling unfolds it, GitHub #138); detail panel on click/hover (header with bonds, then 特质 — the operator's own effect — right under it, 特性, stats (live: the battle's own numbers / the start-of-battle ones in prep, §18.5), skill, module, equipped items, talents: §17.5); enemy preview drawer (next round enemies with counts, factions; its 本局信息 tab lists the briefing's disabled bonds and banned operators, §21.28); 机变 overlay (the official card: framed icon + name, the effect text — data `descRaw` — under it, the taker's round avatar at the top-right; two taps, §18.2, §20.7); merge reward overlay (the promotion reward, or a special offer — 凯瑟琳's 定向投放 … — as item / chess cards under its source's label, with the count of offers queued behind it, §21.2); phase banners; the round's result box at SETTLE (the official 「作战结束」 + 「全员无伤！」 / 「生命值减少 −N」 for the viewer's own LP — after a 联防 the server's charge, `m.public.uniteResult.losses` — with the matching BATTLEOVER sound; none in the boss rounds or for a viewer not in the round; GitHub #235, PR #112); ticker (by broadcast priority, highest first; a leader-damage line plays only in its round and a player's newer one replaces the older, §21.10); toasts; emote wheel; settings (volume, quality, show damage numbers)), **Result** (victory/defeat, rounds, per-player lineup, stats, titles, back to room).

docs/history/0.2.4.md

@@ -274,3 +274,10 @@ enemy: picking emitted a unit click with no definition, instead of the tile clic
 engine-canvas regression retains the card/100 HP assertions and also covers another field refresh, live HP loss and
 closing the card when the crate is destroyed. Device metadata supplied by the new entry still wins; changing fields
 does not carry old devices across. Gameplay and allied targeting rules are unchanged.
+
+### 29.15 Ammunition readout
+
+Active ammunition skills show remaining rounds and magazine capacity below the segmented bar (§10), including
+Laterano's extra rounds and refills. The renderer reads the existing exact snapshot counts rather than estimating
+them from SP. Missing ammunition snapshots, preparation and death hide the number. Dense magazines retain their
+numeric readout when the renderer omits cell separators. Combat rules and golden results are unchanged.