Operator battle voices: the official combat lines play by voice slot during battles, one at a time (#73)

Deploy, skill and result lines come from the operators' official voice slots; a newer line takes the channel over (stale callbacks of the replaced line no longer release it), and the result line is spoken by an operator of the player's own battle. Contributed by @Convey123.

test/fetch-assets-shrink.test.js

@@ -68,6 +68,10 @@ test('fetch-assets shrink guard: the committed manifest minus some audio entries
   assert.deepEqual(shrinkGuard(null, next, parseArgs([])), { dropped: [], write: true }, 'no current manifest: written');
   assert.equal(parseArgs(['--allow-shrink']).allowShrink, true);
   assert.throws(() => parseArgs(['--allow-shrinks']), /unknown option/);
+  // 干员战斗语音: the prep-only slots are opt-in (DESIGN §21.30 — no battle requests them)
+  assert.equal(parseArgs([]).voiceAll, false, 'the battle slots are what a plain run plans');
+  assert.equal(parseArgs(['--voice-all']).voiceAll, true);
+  assert.equal(parseArgs(['--voice-lang=jp']).voiceLang, 'jp');
   assert.equal(statSync(MANIFEST).mtimeMs, before, 'importing the tool runs nothing');
 });