fix(extensions): parse SKILL.md on the --- delimiter line during removal

[Quratulain-bilal]

ExtensionManager._unregister_extension_skills verifies an installed skill before deleting it by reading metadata.source back from its SKILL.md. It located the closing frontmatter delimiter with a raw split("---", 2).

That substring split stops at the first --- anywhere after the opening delimiter — including one embedded in a command description (e.g. "Separate sections with --- markers"). The frontmatter is then truncated mid-value, metadata.source parses empty, the skill looks unrelated to the extension, and its directory is left orphaned on uninstall.

This is the same class of bug fixed in #3590 for CommandRegistrar.parse_frontmatter (content.find("---", 3)), which now scans on line boundaries. The two removal paths here were the remaining substring-split sites reading generated SKILL.md files.

Fix

Parse on the --- delimiter line by reusing the line-anchored CommandRegistrar.parse_frontmatter (the #3590 parser) in both removal paths:

• the fast, registry-driven path, and
• the fallback directory-scan path.

Repro

raw = '''---
name: speckit-myext-report
description: Separate sections with --- markers
metadata:
  source: extension:myext
---
Body here.
'''
# old: raw.split("---", 2)[1] -> "\nname: ...\ndescription: Separate sections with "
#      -> metadata.source == ""  -> dir treated as unrelated, orphaned

Test

Added test_skills_removed_when_description_contains_dashes: installs an extension whose command description contains ---, removes it, and asserts the skill directory is gone. It fails before the fix (assert not skill_dir.exists() → dir orphaned) and passes after. Full tests/test_extension_skills.py, test_extensions.py, and test_extension_registration.py suites pass (467 tests).

[Copilot]

Pull request overview

Fixes orphaned extension skill directories when descriptions contain ---.

Changes:

• Reuses line-anchored frontmatter parsing in both removal paths.
• Adds regression coverage for the primary removal path.

Show a summary per file

File	Description
src/specify_cli/extensions/__init__.py	Corrects SKILL.md ownership parsing during removal.
tests/test_extension_skills.py	Adds dashed-description removal regression coverage.

Review details

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• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Medium

[mnriem]

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