fix: restore Cursor and Kiro installers

[avifenesh]

What changed

• restore the Cursor and Kiro discovery/transform APIs expected by the CLI
• add regression coverage that runs both platform installers through their public entry points
• scope Jest worktree ignores so package-local tests run consistently from linked worktrees
• remove the unused production js-yaml dependency, eliminating GHSA-52cp-r559-cp3m exposure

Root cause

A shared-core sync removed the Cursor and Kiro exports while the AgentSys installer continued calling them. The result was a runtime TypeError for both platforms.

Validation

• full Jest suite — 88 suites passed; 3,521 tests passed, 39 skipped
• npm run validate — all validators passed
• npm run preflight — 16 passed, 0 failed
• npm audit --omit=dev --audit-level=high — 0 vulnerabilities
• packaged CLI smoke — Cursor installed 25 commands and 39 skills; Kiro installed 25 prompts, 39 skills, and 37 agents, with all generated JSON parsing successfully
• canonical agent-core tests — 74 passed, 2 skipped

Dependency

The canonical shared implementation is in agent-sh/agent-core#26 and should merge first. This PR keeps AgentSys working immediately and preserves the fix through the current bundled source.

Closes #380

[gemini-code-assist]

Caution

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[gemini-code-assist]

Caution

The consumer version of Gemini Code Assist on GitHub has been sunset. All code review activity has officially ceased.

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