读了iOS/Android真实源码后修正：busy确实是真实的通话状态，之前判断错了

早前(Part I/K)判断"busy从未在持久化消息里真实出现过，只是本应用自己在
live信令上用的值"，所以没把它并入 CallWebrtcState，只在本地 UI 状态单独
加了个 union。这次拿到手机端真实源码核对，iOS(ServerMessages.swift的7态
枚举)和Android(MsgServerData.java的BUSY)都把busy当成服务端下发的正式
head.webrtc取值之一，和accepted/finished等其余几个是同一级别的东西，
不是本应用凭空发明的——之前的判断依据不足。

补上 case 'busy' 的通话结果文案（"对方忙线中"，和已有的实时来电忙线提示
用词一致），去掉 stores/calls.ts 里两处不再需要的 `| 'busy'` 单独union。

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/lib/messages/dispatch.ts

@@ -156,10 +156,12 @@ export function formatCallDuration(ms: number): string {
  * 1953/1954): `missed` alone covers both "未接听" and "已取消" (a callee who let it ring out and a
  * caller who cancelled before pickup both replace to the SAME wire value) -- direction picks the
  * text, not the wire value, using `mine` (was the ORIGINAL invite sent by me, i.e. was I the
- * caller) exactly the way this app already threads that prop through MessageRow. No `busy` value
- * exists in the confirmed real enum (only accepted/finished/disconnected/missed/declined) despite
- * the old app's own UI vocabulary having one -- not rendered here since nothing legitimate can
- * produce it yet.
+ * caller) exactly the way this app already threads that prop through MessageRow. `busy` WAS assumed
+ * to never appear in a persisted message (only ever seen on this app's own live, ephemeral
+ * `sendCallHangup(...,'busy')` signal) -- disproven by reading the real iOS/Android source
+ * (2026-09-25): both platforms' own SDKs declare `busy` as a genuine `head.webrtc` enum member the
+ * SERVER controls, same as every other case here, so a persisted busy result is a real thing this
+ * app can receive, not just something it can locally signal to a live peer.
  */
 export function callResultDisplay(msg: StoredMessage, mine: boolean): { icon: string; text: string; danger: boolean } | null {
   const content = callContentOf(msg);
@@ -177,6 +179,8 @@ export function callResultDisplay(msg: StoredMessage, mine: boolean): { icon: st
       return { icon: 'phone_missed', danger: true, text: '已拒绝' };
     case 'disconnected':
       return { icon: 'phone_missed', danger: true, text: '异常结束' };
+    case 'busy':
+      return { icon: 'phone_missed', danger: true, text: '对方忙线中' };
     case 'accepted':
     case 'started':
       return { icon, danger: false, text: '通话中' };

web/src/lib/tinode/calls.ts

@@ -21,8 +21,13 @@ export interface CallContent {
 }
 
 /** `head.webrtc` values a call message cycles through, replacing the SAME `seq` in place (doc line
- *  1953) -- `started` is the live invite; the rest are terminal results the server writes over it. */
-export type CallWebrtcState = 'started' | 'accepted' | 'finished' | 'disconnected' | 'missed' | 'declined';
+ *  1953) -- `started` is the live invite; the rest are terminal results the server writes over it.
+ *  `busy` was previously excluded here (assumed to be a client-only, never-persisted value -- see
+ *  the now-superseded reasoning this replaced in stores/calls.ts/dispatch.ts) until reading the real
+ *  iOS/Android app source (2026-09-25 cross-client audit) confirmed it's a genuine enum member both
+ *  platforms' own SDKs declare for this exact server-controlled field (`ServerMessages.swift`'s
+ *  7-case enum, `MsgServerData.java`'s `BUSY`), not a web-only invention. */
+export type CallWebrtcState = 'started' | 'accepted' | 'finished' | 'disconnected' | 'missed' | 'declined' | 'busy';
 
 export function callContentOf(msg: StoredMessage): CallContent | null {
   const webrtc = msg.head?.webrtc;

web/src/stores/calls.ts

@@ -42,11 +42,10 @@ interface CallState {
   // stays true even when the mic never actually attaches at all (permission denied/no device) -- a
   // real user reported this as "看起来接通了" for a call where no audio ever worked on either side.
   mediaJoined: boolean;
-  // `'busy'` is never a real PERSISTED `head.webrtc` value (confirmed live, see dispatch.ts's own
-  // comment) so it's deliberately NOT part of `CallWebrtcState` -- but it IS a real value this app's
-  // own `sendCallHangup(..., 'busy')` puts on the LIVE, ephemeral `{info hang-up}` signal a second
-  // caller receives, which flows straight into this same field.
-  endReason: CallWebrtcState | 'busy' | null;
+  // `busy` is now part of CallWebrtcState itself (2026-09-25: confirmed against real iOS/Android
+  // source that the server genuinely uses this value, not just this app's own live
+  // `sendCallHangup(..., 'busy')` signal a second caller receives) -- no separate union needed here.
+  endReason: CallWebrtcState | null;
   /** Was THIS session the one that placed the call (via startCall), not the one that received it --
    *  needed to pick "已取消" vs "未接听" for the same wire value the same way dispatch.ts's
    *  callResultDisplay already does for the permanent chat-bubble record of the same call. */
@@ -65,7 +64,7 @@ interface CallState {
   switchCamera: () => Promise<void>;
   setHasRemoteVideo: (v: boolean) => void;
   _reset: () => void;
-  _endWithReason: (reason: CallWebrtcState | 'busy') => void;
+  _endWithReason: (reason: CallWebrtcState) => void;
 }
 
 const IDLE = {