feat: pending-finish proposals and QQ image input

Proposal semantics: worker results no longer distinguish success/fail;
only an explicit finish settles a pending proposal. Pending owner input
follows up by resuming the original worker session. Dirty pending blocks
start_next globally; clean pending only blocks its owner.

QQ adapter now downloads image attachments and passes them as ACP image
content blocks; video/file attachments degrade to link text.

.kimi-code/skills/gori-agent-deploy/SKILL.md

@@ -78,7 +78,7 @@ whenToUse: 当用户要求部署、更新、重启、配置 gori-agent Bot（如
    bin/gori-agent status <bot-id>
    ```
    - Health 必须是 HTTP 200 且 bot/platform identity verified。
-   - restart 前检查是否有 `working` Proposal；working 时先告知用户，避免把 worker 打成 `worker_lost`。
+   - restart 前检查是否有 `working` Proposal；working 时先告知用户，避免把 worker 打成 `worker_lost`（重启后该 Proposal 会变为 `pending` 且 `workspaceDirty: true`，需要用户 finish 或 follow_up，并会全局阻塞 start_next）。
 
 ## Assistant / Worker 模型配置