feat(ask): 键盘常态提供 ✏️ 输入自定义答案 按钮

- 每个带选项的提问键盘固定追加第三行 ✏️ 输入自定义答案
- 点击后该题进入待文本状态（textWanted），丢弃该题已点选的按钮项
- 下一条文本消息自动填充最先待文本的题；带 1:/2: 前缀的作答同样可清除待文本状态
- 已实测：✏️ → 发送 111 → custom 答案正确回流

lib/bridge.js

@@ -1464,6 +1464,7 @@ export class TelegramBridge {
                     at: Date.now(),
                     kbSel: new Map(),
                     textAnswers: new Map(),
+                    textWanted: new Set(),
                 };
                 this.pendingAsks.set(String(chatId), pending);
                 void this.deliverAskPrompt(Number(chatId), pending);
@@ -1492,6 +1493,8 @@ export class TelegramBridge {
                                 text: `${j + 1}. ${o.label}`.slice(0, 48),
                                 callback_data: `${ASK_CB}${i}:${j}`,
                             }]),
+                        // Standing third choice: free-text answer, always available.
+                        [{ text: '✏️ 输入自定义答案', callback_data: `${ASK_CB}${i}:custom` }],
                         ...(q.multiSelect ? [[{ text: '✅ 提交所选', callback_data: `${ASK_CB}${i}:ok` }]] : []),
                     ],
                 };
@@ -1557,8 +1560,15 @@ export class TelegramBridge {
                     parts.push([null, line]);
             }
             if (parts.some(([idx]) => idx === null)) {
-                await this.enqueueNotice(chatId, `共 ${questions.length} 个问题，请每行用 1:/2: 前缀分别作答`);
-                return;
+                // ✏️ free-text route: a question awaiting text absorbs the whole message.
+                const target = [...pending.textWanted].sort((a, b) => a - b)[0];
+                if (target !== undefined) {
+                    parts = [[target, text.trim()]];
+                }
+                else {
+                    await this.enqueueNotice(chatId, `共 ${questions.length} 个问题，请每行用 1:/2: 前缀分别作答`);
+                    return;
+                }
             }
         }
         for (const [idx, raw] of parts) {
@@ -1588,6 +1598,7 @@ export class TelegramBridge {
             else {
                 pending.textAnswers.set(idx, { id: q.id, selected: [], custom: cleaned });
             }
+            pending.textWanted.delete(idx);
         }
         // Keyboard selections take precedence per question; resolve when complete.
         if (!this.finalizeAskIfComplete(chatId, pending)) {
@@ -1612,6 +1623,14 @@ export class TelegramBridge {
             return;
         }
         const opts = Array.isArray(q.options) ? q.options : [];
+        if (action === 'custom') {
+            // Free-text path: discard button selections for this question and wait
+            // for the user's next text message (routed via textWanted).
+            pending.kbSel.delete(qi);
+            pending.textWanted.add(qi);
+            await this.client.answerCallbackQuery(cq.id, '请直接发送你的答案文本');
+            return;
+        }
         if (action === 'ok') {
             if (!pending.kbSel.get(qi)?.size) {
                 await this.client.answerCallbackQuery(cq.id, '请先点选选项');