fix(prompts): preserve scoped instruction context

[RerankerGuo]

Description | 描述

Preserve explicit scene/context limits when L1 extracts or deduplicates instruction memories.

This is a conservative first step for scoped instructions:

• Tells L1 extraction to keep explicit applicability conditions in content instead of generalizing them into unconditional global rules.
• Tells conflict detection to compare instruction scope during merge/update and preserve all still-valid scope qualifiers in merged_content.
• Adds focused prompt tests so these guardrails stay in place.

This avoids a schema/storage migration while addressing the over-generalization path described in the issue.

Related Issue | 关联 Issue

Fix #48

Change Type | 修改类型

• Bug fix | Bug 修复
• New feature | 新功能
• Documentation update | 文档更新
• Code optimization | 代码优化

Self-test Checklist | 自测清单

• Verified locally | 本地验证通过
• No existing features affected | 无影响现有功能

Additional Notes | 其他说明

Verified with npm test and npm run build using Node v24.15.0.

[Maxwell-Code07]

Nice to see a careful approach to handling scoped instructions. Preserving applicability conditions on extraction is a smart way to avoid over-generalization without a migration. We'll review it soon.