feat(tg): 去掉 '> Thinking…' 思考提示流水

用户要求：不再发送思考指示（assistant/chunk 的 reasoning 分支整段移除，
连带 thinkingSessions 状态与相关清理）。tool/call、tool/result、todo/write、
turn/end 的流水保持不变。

lib/bridge.js

@@ -113,8 +113,6 @@ export class TelegramBridge {
     disposeApprovalHook;
     /** dsh 0.1.5 起 ask 走 'user-questions/request' waterfall（不再有 userQuestions.provider）。 */
     disposeUserQuestionHook;
-    /** sessionId → thinking indicator state (one notice per reasoning phase) */
-    thinkingSessions = new Map();
     /** callId → tool name (tool/result failure notices) */
     callNames = new Map();
     /** sessionId → latest todo snapshot (/mission) */
@@ -199,7 +197,6 @@ export class TelegramBridge {
         this.noticeQueue.clear();
         this.pendingAsks.clear();
         this.pendingApprovalsTG.clear();
-        this.thinkingSessions.clear();
         this.callNames.clear();
         this.lastTodos.clear();
         for (const controller of this.compactAborts.values())
@@ -1101,7 +1098,6 @@ export class TelegramBridge {
         }
         if (event.type === 'turn/end') {
             this.busySessions.delete(id);
-            this.thinkingSessions.delete(id);
             for (const b of targets)
                 this.stopTypingHeartbeat(b.chatId);
             // Abnormal endings (API failure / abort / crash-recovery) must be
@@ -1129,7 +1125,6 @@ export class TelegramBridge {
             const name = event.data?.name ?? 'tool';
             if (name === 'ask_user_question')
                 return;
-            this.thinkingSessions.set(id, false);
             if (event.data?.callId !== undefined) {
                 if (this.callNames.size > 400) {
                     const first = this.callNames.keys().next().value;
@@ -1147,25 +1142,11 @@ export class TelegramBridge {
         }
         if (event.type === 'assistant/message') {
             const text = contentToText(event.data.message.content);
-            this.thinkingSessions.set(id, false);
             if (!text)
                 return;
             await Promise.all(targets.map((b) => this.deliver(b.chatId, text)));
             return;
         }
-        if (event.type === 'assistant/chunk') {
-            // Thinking indicator: once per reasoning phase, status only (no content).
-            const chunk = event.data?.chunk;
-            const ctype = String(chunk?.type ?? '');
-            const btype = String(chunk?.block?.type ?? '');
-            const isReasoning = ctype.includes('reasoning') || btype.includes('reasoning') || btype.includes('think');
-            if (isReasoning && this.thinkingSessions.get(id) !== true) {
-                this.thinkingSessions.set(id, true);
-                for (const b of targets)
-                    this.enqueueNotice(b.chatId, '> Thinking…');
-            }
-            return;
-        }
         if (event.type === 'tool/result') {
             // Only failures — successful results are too noisy for the phone.
             const data = event.data;