fix: expose ideate and code components to native Copilot plugins

[danielmeppiel]

Summary

• Map ideate-kit skills to ./.apm/skills/ and code-kit agents to ./.apm/agents/ in their legacy .claude-plugin/plugin.json manifests.
• Keep the existing APM payloads, marketplace, metadata, and versions unchanged; document why the source mappings must be preserved.
• Enables native Copilot source-marketplace discovery without moving/copying payloads or introducing Agent Plugins schemas.

Validation

• Read-only JSON/path assertions resolve plugins/ideate-kit/.apm/skills/meeting-to-issue/SKILL.md and plugins/code-kit/.apm/agents/architect.agent.md via the marketplace and mapped component directories; all other manifest fields are unchanged.
• apm audit --ci --no-policy passes.
• apm pack --offline --dry-run passes independently for both scoped kits and retains the expected skill/agent output.
• APM 0.14.0 and 0.31.0 exporter source confirms packed manifests normalize component paths to the generated convention layout, separately from authored source manifests.
• git diff --check passes. No plugins or plugin hooks were installed or executed.

Existing local-tool drift (not changed)

The locally installed APM 0.31.0 reports marketplace drift on the untouched baseline 931cfb58663154415f8a13e14680f548114d4555 (new category/version metadata and a Codex marketplace). Baseline remote self-audit passed. This PR intentionally does not regenerate unrelated marketplace outputs or realign releases.

Reference: Copilot legacy component path fields.