0.2.3: prepare follow-up fixes and client features (#407, #408, #410, #413, #431, #435, #436, #440, #444)

Add special-target activation without bypassing attack cadence, cooperative
card preferences and emotes, skill sound banks, per-operator voice choices,
text sizing, install prompts, closed-tab recovery and unanimous setup rerolls.
Retain late deployment elapsed time and resolve echo/counter pulses without
recursive hook overflow. Independent final review remains pending.

Golden: roster-016, roster-035, roster-036, roster-045;
boss-boss_1-pair, boss-boss_3-pair, boss-boss_5-pair, boss-boss_7-pair,
hidden-boss_9-pair; solo-HARD-9-boosted: Lemuen attack cadence.
diy-132: Necras extra activation targets.
coop2-NORMAL-14-standins: cooperative purchase preference and simulation fixes.
hidden-boss_10-solo: echo pulse FIFO resolution.
See DESIGN 28.13-28.24 for assumptions, sources and contributor credit.

public/js/pwa.js

@@ -0,0 +1,40 @@
+// Install prompts are browser-issued, one-use capabilities. No service worker or application cache is installed.
+export function createPwaInstall(win) {
+  let prompt = null, installed = false;
+  const listeners = new Set();
+  const display = win?.matchMedia?.('(display-mode: standalone), (display-mode: fullscreen)');
+  const available = () => !!prompt && !installed && !display?.matches && !win?.navigator?.standalone;
+  const emit = () => { for (const fn of listeners) fn(available()); };
+  const offer = (event) => {
+    if (installed || display?.matches || win?.navigator?.standalone || typeof event.prompt !== 'function') return;
+    event.preventDefault();
+    prompt = event;
+    emit();
+  };
+  const done = () => { installed = true; prompt = null; emit(); };
+  win?.addEventListener?.('beforeinstallprompt', offer);
+  win?.addEventListener?.('appinstalled', done);
+  display?.addEventListener?.('change', emit);
+  return {
+    available,
+    subscribe(fn) { listeners.add(fn); fn(available()); return () => listeners.delete(fn); },
+    async request() {
+      if (!available()) return false;
+      const event = prompt;
+      prompt = null; // Consume before awaiting: dismissal, rejection and repeated clicks cannot reuse this event.
+      emit();
+      try {
+        const result = await event.prompt();
+        const choice = event.userChoice ? await event.userChoice : result;
+        return choice?.outcome === 'accepted';
+      } catch { return false; }
+    },
+    dispose() {
+      win?.removeEventListener?.('beforeinstallprompt', offer);
+      win?.removeEventListener?.('appinstalled', done);
+      display?.removeEventListener?.('change', emit);
+      prompt = null; listeners.clear();
+    },
+  };
+}
+export const pwaInstall = createPwaInstall(globalThis.window);