Update all documentation, code, and tests to use the new endpoint formats:
- MCP: /api/mcp/{username}/{collection-slug}/{transport}
- Agent: /api/{username}/agents/{agent-uid}/conversation/{id}
Changes include:
- Update MCP URLs in collections page, docs, and test script
- Update agent API URLs in chat page, docs, tests, and cron job
- Add API key authentication requirements to all examples
- Update ARCHITECTURE.md with correct endpoint formats
- Update discord cron job to fetch owner username for new URL format
- Move endpoint from /api/collections/[id]/mcp to /api/collections/[id]/mcp/[transport]
- Support both 'http' and 'sse' transports
- HTTP: standard JSON-RPC over HTTP
- SSE: Server-Sent Events for streaming responses
- Add test script for validating MCP endpoints
