fix(channels) : route Telegram replies to the correct forum topic

[tranvantruonggit]

What this PR does

Routes Telegram bot replies back to the same forum topic the user messaged from, instead of always landing in #general. Does this by caching the threadId from inbound envelopes and passing it through sendMessage to sendTelegramMessage.

Why it's needed

When a Qwen Code Telegram bot is used in a supergroup with Topics enabled, all bot replies appear in #general regardless of which topic the user messaged from. sessionScope: "thread" creates isolated sessions per topic, but outbound replies don't route back to the correct thread.

Closes #7609

Reviewer Test Plan

1. Create a Telegram supergroup with Topics enabled
2. Add the bot to the group
3. Send a message in a specific topic (not #general)
4. Before fix: bot reply appears in #general
5. After fix: bot reply appears in the same topic the user messaged from

Risk & Scope

• Risk: Low. The change is local to TelegramChannel — it adds a chatId → threadId cache populated from inbound message handlers. If threadId is not in the cache (e.g. DM, non-topic group, or first message), sendTelegramMessage receives undefined and behaves exactly as before.
• Out of scope: Typing indicators still go to #general (they don't go through sendMessage). This can be addressed separately if needed.

Linked Issues

Closes #7609

[qwen-code-ci-bot]

@tranvantruonggit Thanks for the fix — the approach looks right at a glance, but the PR body is empty (just Closes #7609). The PR template requires a few sections so reviewers can evaluate the change without digging through the issue thread:

• What this PR does — one or two sentences on the change
• Why it's needed — link the issue and summarize the problem
• Reviewer Test Plan — how to verify (steps, expected vs. observed behavior)
• Risk & Scope — main risk, what's out of scope
• Linked Issues — Closes #7609 (already there, just needs the heading)

Could you fill those in? Once the template is complete we can move straight to code review.

中文说明

@tranvantruonggit 感谢提交修复——方案看起来是对的，但 PR 描述目前是空的（只有 Closes #7609）。PR 模板要求填写以下几个部分，方便 reviewer 快速评估：

• What this PR does — 一两句话描述改动
• Why it's needed — 关联 issue，说明问题背景
• Reviewer Test Plan — 如何验证（步骤、预期 vs 实际行为）
• Risk & Scope — 主要风险、不在范围内的内容
• Linked Issues — Closes #7609（已有，加上标题即可）

麻烦补充一下，模板完整后我们直接进入代码审查。

— Qwen Code · qwen3.8-max-preview

[tranvantruonggit]

I updated the PR

[tranvantruonggit]

"Superseded by the more comprehensive #7612"