fix(core): ignore blank task list filters

[AaronZ345]

What this PR does

• Treats blank task_list owner and blockedBy filter strings as omitted optional filters.
• Adds regression coverage for blank owner and blocked-by filters.

Why it's needed

Blank optional filters currently activate literal filtering, which can make a populated task list appear empty or reject an otherwise omitted owner filter. Normalizing blanks at the tool boundary matches the public optional-filter contract without changing nonblank validation behavior.

Fixes #9281.

Reviewer Test Plan

• npx vitest run packages/core/src/tools/task-list.test.ts -t "treats a blank"
• npx vitest run packages/core/src/tools/task-list.test.ts
• npx prettier --check packages/core/src/tools/task-list.ts packages/core/src/tools/task-list.test.ts

Notes

中文说明

本 PR 修复 task_list 对空白 owner / blockedBy 可选过滤参数的处理：空白字符串现在会被视为未传入，而不是触发空结果或 owner 校验错误。非空但非法的 owner（例如 !!!）仍然保持原有拒绝行为。

[yiliang114]

Thanks for the contribution! This one overlaps with #9286, which was opened earlier (Aug 16) for the same issue #9281 and already has a CI-approved review in progress. To avoid duplicated effort, I'll close this in favor of that one — really appreciate the work you put into it, and please feel free to pick up any other open issues that haven't been claimed yet. 🙏

[qwen-code-ci-bot]

✅ Qwen Triage finished — view run. See the stage comments in this thread for the result.

✅ Qwen Triage 已完成 —— 查看运行。结果见本线程中的各阶段评论。

[qwen-code-ci-bot]

⏭️ Qwen Triage skipped — this PR was already closed unmerged by @yiliang114 (as a duplicate of #9286, which targets the same issue #9281 and was opened earlier), so there is nothing to gate or review here. The fix continues in #9286. Thanks for the contribution anyway, @AaronZ345 — please feel free to pick up another open issue. 🙏

中文说明

⏭️ Qwen Triage 已跳过 —— 本 PR 已由 @yiliang114 关闭（未合并）：它与更早提交的 #9286 重复，两者针对同一个 issue #9281。因此没有需要评审的内容，修复工作继续在 #9286 中进行。感谢 @AaronZ345 的贡献，欢迎认领其他尚未被接手的 issue。🙏

— Qwen Code · qwen3.8-max