feat: 记忆注入增加来源标注和统一时间戳

[lishuceo]

Summary

• 记忆注入时标注来源：区分"当前会话"和"来自其他会话"的记忆，帮助模型理解上下文边界
• 所有记忆类型统一附带日期标注（之前 preference/relation 没有时间信息）
• decision 类型优先使用 createdAt（决策时间），其他类型优先使用 validAt

背景

用户在私聊中发现 bot 携带了来自其他群聊话题的记忆上下文，虽然记忆系统按 user 维度共享是合理设计，但缺少来源标注会让模型混淆上下文。

改动

• src/memory/injector.ts: InjectionContext 新增 chatId，formatMemories 增加来源和日期标注逻辑
• src/feishu/event-handler.ts: 两处 injectMemories 调用传入 chatId
• src/memory/__tests__/injector.test.ts: 新增 3 个测试用例覆盖来源标注场景

Test plan

• injector.test.ts 20/20 通过
• 全量回归 944/945 通过（1 个失败为已知无关问题 quality.test > 当前工作重点）

🤖 Generated with Claude Code

[claude]

Claude finished @lishuceo's task in 1m 39s —— View job

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PR #123 Review: 记忆注入增加来源标注和统一时间戳

• Check for previous review comments
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• Review code for issues
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✅ Approved

Clean, well-structured change. The refactoring of the annotation logic into a unified annotations[] builder pattern is a nice improvement over the previous branching approach.

What looks good:

• InjectionContext.chatId is optional, maintaining backward compatibility
• Both call sites (executeClaudeTask L1279, executeDirectTask L1630) correctly have chatId in scope as a function parameter
• The fromOtherChat guard (currentChatId && mem.chatId && mem.chatId !== currentChatId) properly handles null/undefined cases
• The unified annotation builder ensures confidence: low is now applied to all memory types (previously it was only shown for items that didn't match the state/fact/decision branches — a subtle improvement)
• Test coverage is solid: 3 new test cases covering other-chat tagging, same-chat non-tagging, and no-chatId non-tagging
• Decision to use createdAt for decisions vs validAt for others is semantically sound

Minor observation (not blocking):

• The old code annotated facts with (since ${date}) — the "since" prefix gave semantic context that the fact has been true since that date. The new code shows bare dates like (2026-02-15) for all types. This is fine but slightly less informative for facts. Consider whether a type-specific prefix (e.g., "since" for facts, "decided" for decisions) would help the model better interpret the dates. This is entirely optional and cosmetic.

Note: I was unable to run the test suite due to tool permission restrictions, but the tests are well-written and the PR description confirms 20/20 passing.

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