feat(copilot): support --integration-options="--skills" for skills-based scaffolding (#2324)

* Initial plan

* feat(copilot): add --skills flag for skills-based scaffolding

Add --skills integration option to CopilotIntegration that scaffolds
commands as speckit-<name>/SKILL.md under .github/skills/ instead of
the default .agent.md + .prompt.md layout.

- Add options() with --skills flag (default=False)
- Branch setup() between default and skills modes
- Add post_process_skill_content() for Copilot-specific mode: field
- Adjust build_command_invocation() for skills mode (/speckit-<stem>)
- Update dispatch_command() with skills mode detection
- Parse --integration-options during init command
- Add 22 new skills-mode tests
- All 15 existing default-mode tests continue to pass

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* docs(AGENTS.md): document Copilot --skills option

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* Potential fix for pull request finding 'Unused local variable'

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* fix: address PR #2324 review feedback

- Reset _skills_mode at start of setup() to prevent singleton state leak
- Tighten skills auto-detection to require speckit-*/SKILL.md (not any
  non-empty .github/skills/ directory)
- Add copilot_skill_mode to init next-steps so skills mode renders
  /speckit-plan instead of /speckit.plan
- Fix docstring quoting to match actual unquoted output
- Add 4 tests covering singleton reset, auto-detection false positive,
  speckit layout detection, and next-steps skill syntax
- Fix skipped test_invalid_metadata_error_returns_unknown by simulating
  InvalidMetadataError on Python versions that lack it

* fix: inline skills prompt in dispatch_command auto-detection path

build_command_invocation() reads self._skills_mode which stays False
when skills mode is only auto-detected from the project layout. Inline
the /speckit-<stem> prompt construction so dispatch_command() sends the
correct prompt regardless of how skills mode was detected.

Also strengthen test_dispatch_detects_speckit_skills_layout to assert
the -p prompt contains /speckit-plan and the user args.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: mnriem <15701806+mnriem@users.noreply.github.com>
Co-authored-by: Copilot Autofix powered by AI <223894421+github-code-quality[bot]@users.noreply.github.com>

src/specify_cli/__init__.py

@@ -1268,6 +1268,12 @@ def init(
                 integration_parsed_options["commands_dir"] = ai_commands_dir
             if ai_skills:
                 integration_parsed_options["skills"] = True
+            # Parse --integration-options and merge into parsed_options so
+            # flags like --skills reach the integration's setup().
+            if integration_options:
+                extra = _parse_integration_options(resolved_integration, integration_options)
+                if extra:
+                    integration_parsed_options.update(extra)
 
             resolved_integration.setup(
                 project_path, manifest,
@@ -1393,8 +1399,10 @@ def init(
             }
             # Ensure ai_skills is set for SkillsIntegration so downstream
             # tools (extensions, presets) emit SKILL.md overrides correctly.
+            # Also set for integrations running in skills mode (e.g. Copilot
+            # with --skills).
             from .integrations.base import SkillsIntegration as _SkillsPersist
-            if isinstance(resolved_integration, _SkillsPersist):
+            if isinstance(resolved_integration, _SkillsPersist) or getattr(resolved_integration, "_skills_mode", False):
                 init_opts["ai_skills"] = True
             save_init_options(project_path, init_opts)
 
@@ -1506,7 +1514,7 @@ def init(
     # Determine skill display mode for the next-steps panel.
     # Skills integrations (codex, kimi, agy, trae, cursor-agent) should show skill invocation syntax.
     from .integrations.base import SkillsIntegration as _SkillsInt
-    _is_skills_integration = isinstance(resolved_integration, _SkillsInt)
+    _is_skills_integration = isinstance(resolved_integration, _SkillsInt) or getattr(resolved_integration, "_skills_mode", False)
 
     codex_skill_mode = selected_ai == "codex" and (ai_skills or _is_skills_integration)
     claude_skill_mode = selected_ai == "claude" and (ai_skills or _is_skills_integration)
@@ -1514,7 +1522,8 @@ def init(
     agy_skill_mode = selected_ai == "agy" and _is_skills_integration
     trae_skill_mode = selected_ai == "trae"
     cursor_agent_skill_mode = selected_ai == "cursor-agent" and (ai_skills or _is_skills_integration)
-    native_skill_mode = codex_skill_mode or claude_skill_mode or kimi_skill_mode or agy_skill_mode or trae_skill_mode or cursor_agent_skill_mode
+    copilot_skill_mode = selected_ai == "copilot" and _is_skills_integration
+    native_skill_mode = codex_skill_mode or claude_skill_mode or kimi_skill_mode or agy_skill_mode or trae_skill_mode or cursor_agent_skill_mode or copilot_skill_mode
 
     if codex_skill_mode and not ai_skills:
         # Integration path installed skills; show the helpful notice
@@ -1535,7 +1544,7 @@ def init(
             return f"/speckit-{name}"
         if kimi_skill_mode:
             return f"/skill:speckit-{name}"
-        if cursor_agent_skill_mode:
+        if cursor_agent_skill_mode or copilot_skill_mode:
             return f"/speckit-{name}"
         return f"/speckit.{name}"
 
@@ -2166,7 +2175,7 @@ def _update_init_options_for_integration(
     opts["context_file"] = integration.context_file
     if script_type:
         opts["script"] = script_type
-    if isinstance(integration, SkillsIntegration):
+    if isinstance(integration, SkillsIntegration) or getattr(integration, "_skills_mode", False):
         opts["ai_skills"] = True
     else:
         opts.pop("ai_skills", None)