fix: remove unsupported mode: frontmatter from Copilot skills mode

[lselvar]

Fixes #2799

Summary

• Removes the mode: frontmatter field injected into SKILL.md files when initializing with --integration copilot --integration-options "--skills"
• VS Code Copilot Agent Skills do not support mode: as a valid frontmatter field — the Agent Skills spec only recognizes name, description, user-invocable, and disable-model-invocation
• The field was injected by CopilotIntegration.post_process_skill_content() as mode: speckit.<stem> (e.g. mode: speckit.plan). After removing it, Copilot correctly picks up and executes the generated skills

Changes

src/specify_cli/integrations/copilot/__init__.py

• Simplified post_process_skill_content() to delegate directly to _CopilotSkillsHelper.post_process_skill_content() without injecting mode:
• Removed ~50 lines of frontmatter-parsing and injection logic

tests/integrations/test_integration_copilot.py

• test_post_process_skill_content_injects_mode → test_post_process_skill_content_does_not_inject_mode: asserts mode: is absent
• test_post_process_skill_content_injects_hook_note: removes assertion for mode:, retains assertion for shared hook guidance (replace dots)
• test_skills_have_mode_in_frontmatter → test_skills_do_not_have_mode_in_frontmatter: asserts generated SKILL.md files have no mode key in frontmatter

tests/integrations/test_integration_subcommand.py

• Updated Copilot extension skills test to assert mode: is absent from generated SKILL.md

Test plan

• Run focused tests:

  uv run --extra test pytest tests/integrations/test_integration_copilot.py tests/integrations/test_integration_subcommand.py -v

  Expected: 110 passed
• Run specify init --here --integration copilot --integration-options "--skills" and confirm generated SKILL.md files contain no mode: field
• Confirm Copilot correctly discovers and executes the generated skills in VS Code after the fix

AI disclosure: This PR was developed with Claude Code assistance.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes Copilot skills-mode generation by removing the unsupported mode: frontmatter field from generated SKILL.md files, aligning output with VS Code Copilot Agent Skills’ supported frontmatter schema.

Changes:

• Simplifies CopilotIntegration.post_process_skill_content() to delegate to _CopilotSkillsHelper without injecting mode:.
• Updates Copilot integration tests to assert mode: is not injected and is absent from generated skills.
• Updates the integration switch test to validate Copilot skills-mode extension skills don’t include mode:.

Show a summary per file

File	Description
src/specify_cli/integrations/copilot/__init__.py	Removes custom frontmatter parsing/injection logic and stops adding unsupported mode: to Copilot skills.
tests/integrations/test_integration_copilot.py	Updates/renames tests to assert mode: is not injected and not present in generated SKILL.md frontmatter.
tests/integrations/test_integration_subcommand.py	Adjusts Copilot skills-mode extension migration test to assert mode: is absent from the generated skill file.

Copilot's findings

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• Files reviewed: 3/3 changed files
• Comments generated: 0

[mnriem]

Thank you!