Integrate skill discovery fixes / 集成技能发现修复

[SivanCola]

Summary

• Require skill-like frontmatter for flat Markdown files in .claude/skills, so ordinary Claude docs are ignored without warnings.
• Follow symlink and Windows reparse-style skill directory entries when scanning skill roots.
• Combine the overlapping internal/skill changes from Fix Claude skill markdown warnings #4441 and fix(skill): follow Windows linked skill directories #4442 on current main-v2 so they can merge without one PR blocking the other.

Fixes #4417.

Related PRs

• Supersedes Fix Claude skill markdown warnings #4441. Thanks @thomasvan for the Claude Markdown warning fix and regression tests.
• Supersedes fix(skill): follow Windows linked skill directories #4442. Thanks @ferstar for the Windows linked skill directory fix and regression tests.

Authorship note: @SivanCola is the maintainer integrator for this PR. @thomasvan and @ferstar contributed as repository collaborators through #4441 and #4442; their work is acknowledged as part of the shared skill-discovery fix.

Cache impact

• Skill discovery becomes less noisy for .claude/skills flat Markdown and more complete for linked skill directories.
• No per-turn dynamic skill metadata, tool schemas, provider serialization, or prompt construction order changes were introduced beyond deterministic discovery of intended skill files.

Verification

• go test ./internal/skill ./internal/config
• go test ./internal/boot with isolated HOME and XDG_CONFIG_HOME
• go test -run 'TestSkillRootsView|TestCapabilitiesIncludesDisabledSkills|TestNormalizeSkillPath' . from desktop/
• git diff --check

go test ./... was also attempted with isolated HOME and XDG_CONFIG_HOME; only sandbox confinement tests failed because this local runner does not enforce the expected sandbox denial behavior.

[SivanCola]

Contribution note: thanks @thomasvan and @ferstar for the overlapping skill-discovery work in #4441 and #4442.

This integration PR preserves @thomasvan's Claude flat-Markdown warning fix and tests, and @ferstar's Windows linked skill directory fix and tests. @SivanCola is acting as maintainer integrator here; @thomasvan and @ferstar are acknowledged as repository contributors to this shared fix.

[SivanCola]

@codex review

[SivanCola]

Status update: the refreshed clean head f3742f1e passed the full GitHub check set. Normal merge is still blocked by the branch review policy, so I am leaving this open for review rather than using admin bypass or a personal email for auto-merge.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: e4785ef5a6

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".