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/content/choices.test.js

@@ -79,7 +79,10 @@ test('coverage: every 悬赏 / 战术决策 effect and every 道具补给 / 机
   const ids = choiceCardIds(DATA);
   assert.equal(ids.bounty.length, 129, '129 ENEMY_GAIN effects');
   assert.equal(ids.tactic.length, 43, '43 BUFF_GAIN effects');
-  assert.equal(ids.items.length, 56, '56 shop-eligible normal EQUIP items');
+  // 56 normal EQUIP items − the 5 effect-only ones (4 special 维式重锤, 突变细胞: never sold, user playtest #4)
+  assert.equal(ids.items.length, 51, '51 shop items');
+  for (const id of ['chess_item_2_03_e_a', 'chess_item_3_09_e_a', 'chess_item_3_10_e_a', 'chess_item_4_09_e_a', 'chess_item_5_08_e_a']) assert.ok(!ids.items.includes(id), `${id} is never a supply card`);
+  assert.ok(ids.items.includes('chess_item_1_01_e_a'), 'the plain 维式重锤 is');
   for (const id of [...ids.bounty, ...ids.tactic, ...ids.items]) {
     const h = REG.get(`choice:${id}`);
     assert.ok(h && typeof h.onChoicePick === 'function', `choice:${id}`);