fix: align Hermes startup paths

[cairoegy21-byte]

Summary

• centralizes Hermes Agent discovery/startup logic for server runtime and Vite dev mode
• launches current Hermes Agent source checkouts with gateway.run instead of legacy webapi fallback
• fixes Playground HUD JSX syntax so the old typecheck parser failure is gone
• updates MCP fallback wording to reflect local CLI Test bridge support

Test Plan

• pnpm vitest run src/server/claude-agent.test.ts src/server/tests/gateway-capabilities.test.ts --reporter=basic
• pnpm exec tsc --noEmit --pretty false (remaining broad baseline quarantined; no playground-hud parser errors remain)