Playtest #4 fixes: tile picking, knocked-down state, element gauges, draft timer, live stats, shop items, drones, 赫默, 炎佑, UI flash

- #1 picking by the tile under the pointer (prep, battle, pen, equipment drops); the dragged model stays
  under the pointer (mouse and touch); pixel probe removed; phone ghost-click on the underframe fixed
- #2 two-tap confirm on 机变 cards (like the shop)
- #3 a 同盟 room with one human is untimed like 独立模拟 (no countdown outside battles)
- #4 strategy draft: one synced countdown, 30 s per human turn, timeout takes the highlighted band
- #5 special 维式重锤 (4) and 突变细胞 no longer sold; item card shows where they come from
- #6 operator skill-mode sounds no longer play on normal attacks (纯烬艾雅法拉 and 55 others)
- #7 detail card shows live battle stats and the prep-time battle-start stats (g.unitStats)
- #8 official element gauges on units; burst cooldown (阻回) per PRTS
- #9 knocked-down operators stay on their tile with a redeploy countdown ring
- #10 drone behaviour per PRTS (暴鸰, 先兆者 shells, 黑云, 萨科塔之眼)
- #11 赫默's drone only from her skill; placeable summons limited to talent tokens
- #12 炎佑 stays where it is with no enemies; 祛恶之焰 as a continuous channel
- #13 the occasional giant bond icon (loading texture scaled ×46) fixed
- docs (DESIGN §18), recordings, data and tests updated (2467 unit tests, all browser suites green)

test/match/hardening.test.js

@@ -411,8 +411,10 @@ test('audited FakeBattle matches (all phases incl. 联防, 机变, Final Assault
     const h = makeMatch({
       mode: 'coop', difficulty: 'NORMAL', humans: 1, bots: n - 1, seed, fake: true,
       script: (b) => (b.kind === 'boss' ? { bossDps: 5000 } : { leaks: Object.fromEntries(b.players.map((p, i) => [p, (b.round + i + seed) % 3])) }),
-    }).start();
-    h.autoHumans();
+    });
+    // AI-played before the start: a single human's briefing is untimed (Match.soloUntimed, user playtest #4 item 3) and
+    // waits for 准备就绪, which only an autoplaying seat gives by itself
+    h.autoHumans().start();
     const audit = attachAudit(h.m);
     for (const ps of h.m.players.values()) ps.lp = 200;
     h.runToEnd({ maxSteps: 3e6 });