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/merge.test.js

@@ -320,8 +320,9 @@ test('a merge completed during SETTLE (突变细胞) keeps its reward offer for
 test('withdrawing a summoner with a full hand: its own summon stack frees the slot (onto the stack or anywhere)', () => {
   for (const onto of ['stack', 'other']) {
     const { m, ps } = prep(24);
-    const hemo = give(m, ps, 'chess_char_2_02_a');
-    const [r, c] = legalTileFor(m, ps, 'chess_char_2_02_a');
+    // 伺夜: its talent summon 狼群 is a hand card (a skill's summon such as 赫默's drone never is)
+    const hemo = give(m, ps, 'chess_char_3_19_a');
+    const [r, c] = legalTileFor(m, ps, 'chess_char_3_19_a');
     assert.deepEqual(m.handle('p_0', { t: 'g.move', uid: hemo.uid, to: { area: 'board', row: r, col: c } }), { ok: true });
     const stackIdx = ps.hand.findIndex((p) => p && p.kind === 'token' && p.ownerUid === hemo.uid);
     assert.ok(stackIdx >= 0, 'its summon stack went to the hand');