feat(skills): add CLI for skills management

Add skills-cli.ts with commands:
- list: Show all skills with eligibility status
- status [id]: Show detailed skill info or summary
- install <id>: Install skill dependencies

Add skills:cli script to package.json

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -9,6 +9,7 @@
     "agent:cli": "tsx src/agent/cli.ts",
     "agent:interactive": "tsx src/agent/interactive-cli.ts",
     "agent:profile": "tsx src/agent/profile-cli.ts",
+    "skills:cli": "tsx src/agent/skills-cli.ts",
     "dev:gateway": "tsx --watch src/gateway/main.ts",
     "dev:console": "tsx --watch src/console/main.ts",
     "dev:web": "pnpm --filter @multica/web dev",