fix(always-on): tolerate H1 section headers in report markdown

[Gucc111]

Summary

• LLM 在调用 always_on_report 工具时，有时使用 # Plan Reference（H1）而非 ## Plan Reference（H2）作为章节标题，导致 parseReportMarkdown 无法识别任何 section，所有章节被填充为 (empty)，实际详尽的 report 内容被完全丢弃。
• parseReportMarkdown 现在会将 # SectionName（当 SectionName 匹配 required section 名称时）自动降级为 ## SectionName，并在 fallbacks 中记录 h1-downgraded(...) 便于追踪。
• Title 解析不再把匹配 required section 名称的 H1 行误消费为标题。
• Report prompt（英文 + 中文）现在明确要求使用 ##（h2）标题。

Test plan

• 触发一次 Always-On run，观察 report 正常使用 ## 时行为不变
• 手动构造一份使用 #（H1）章节标题的 report content，验证 parseReportMarkdown 能正确提取所有 section 内容，且 fallbacks 包含 h1-downgraded 条目
• 验证第一行为 # Plan Reference（无独立标题行）时，title 回退为默认值 Always-On Discovery Run，且 Plan Reference section 内容被正确提取

Made with Cursor

[Copilot]

Pull request overview

This PR improves robustness of the Always-On work report markdown parsing and reduces the chance of the runtime discarding report content when the LLM uses H1 headers for required sections. It also updates the report-writing prompts (EN + ZH) to explicitly require H2 (##) section headers to avoid producing incompatible markdown.

Changes:

• Update parseReportMarkdown to treat # <RequiredSection> as a valid section header (downgrading H1 to H2 behavior) and record h1-downgraded(...) in fallbacks.
• Fix title parsing so an H1 line matching a required section name is not mistakenly consumed as the report title.
• Clarify report prompts (English + Chinese) to require ## headers for each required report section.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/always-on/runtime/discoveryPrompts.zh.ts	Explicitly requires ## (H2) headers for each report section in the Chinese report prompt.
src/always-on/runtime/discoveryPrompts.ts	Explicitly requires ## (H2) headers for each report section in the English report prompt.
src/always-on/contracts/ReportContract.ts	Makes report parsing tolerant to H1 required-section headers and avoids mis-parsing required-section H1 as the title.

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