fix: 路由 prompt 搜索指令要求验证 .git 目录

[lishuceo]

Summary

• 路由 agent 通过工具 ls 搜索项目目录时，仍会匹配到非仓库目录（如 talktype-target 编译产物），即使 use_existing 验证能拒绝，回退到 use_default 仍不符合预期
• 修复: 在搜索指令中明确告知 agent 只有含 .git 的目录才是有效仓库，部分名称匹配（如 talktype-target ≠ talktype）应继续查找

根因: PR #113 的 discoverLocalProjects 过滤生效后，talktype-target 不再出现在"已知项目"列表中。但路由 agent 走 Rule 6 工具搜索时，ls /root/dev/ 仍然能看到 talktype-target，agent 将其误认为 talktype 项目。

与 PR #113/#114 的关系: 这是第三层防护 — prompt 层面引导 agent 不选错误目录（前两层: 项目列表过滤 + 验证回退）

Test plan

• 42 个路由测试通过

🤖 Generated with Claude Code

[claude]

Claude finished @lishuceo's task in 36s —— View job

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PR Review: fix: 路由 prompt 搜索指令要求验证 .git 目录

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✅ Approved — Clean, minimal, and well-targeted change.

What this does: Enhances the Rule 6 tool-search prompt (line 117 of router.ts) to instruct the routing agent that:

1. Only directories containing .git are valid repositories
2. Build artifact directories (e.g. xxx-target, build) should be skipped
3. Partial name matches (e.g. talktype-target ≠ talktype) should not be accepted

Assessment: This is a sensible third-layer defense complementing PR #113 (project list filtering) and PR #114 (validation fallback). The change is prompt-only — no logic or runtime behavior modified — so the risk is effectively zero. The wording is clear and gives the LLM agent concrete examples of what to avoid, which is good prompt engineering practice.

No issues found. All 42 routing tests passing per the PR description.

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