Emit wardrobe config for Claude and Gemini

[danmestas]

Summary

• Make Claude/Gemini project rules emit shared AGENTS.md plus thin @AGENTS.md shims.
• Add Gemini agent component emission and allow gemini agent targets in validation.
• Emit Claude MCP servers to root .mcp.json.
• Document wardrobe as the canonical source of truth and emitted harness files as derived artifacts.

Test plan

• npx vitest run src/tests/adapters/claude-code.test.ts src/tests/adapters/gemini.test.ts src/tests/validate.test.ts src/tests/content-store.test.ts
• npx vitest run src/tests/ac/up.test.ts src/tests/integration.test.ts src/tests/adapters/gemini/integration.test.ts src/tests/adapters/claude-code.test.ts src/tests/adapters/gemini.test.ts src/tests/validate.test.ts src/tests/content-store.test.ts
• npm ci
• npm run typecheck
• npm run build
• npm link
• npm test (80 files / 633 tests)