Add CLI remote/API mode via MCP StreamableHTTP

[G9Pedro]

Summary

• add remote MCP client wrapper at packages/cli/src/remote-client.ts using StreamableHTTPClientTransport
• add CLI remote-routing for --api-url/WORKGRAPH_API_URL and --api-key/WORKGRAPH_API_KEY across key commands
• route these commands through MCP HTTP when remote mode is enabled: thread list/create/next/claim/done, status, brief, checkpoint, agent register/heartbeat/list, search, query, lens list/show
• add workgraph remote test command to validate connectivity and show available tools/status snapshot
• add missing MCP server tools required by remote flow (workgraph_agent_register, workgraph_agent_heartbeat, workgraph_agent_list, workgraph_search, workgraph_lens_list, workgraph_lens_show)
• update CLI/MCP schema drift snapshots and add integration coverage in tests/integration/remote-cli.test.ts

Testing

• pnpm --filter @versatly/workgraph-cli run typecheck
• pnpm --filter @versatly/workgraph-mcp-server run typecheck
• pnpm exec vitest run --config vitest.config.ts tests/integration/remote-cli.test.ts
• pnpm exec vitest run --config vitest.config.ts packages/kernel/src/schema-drift-regression.test.ts -u
• pnpm exec vitest run --config vitest.config.ts tests/integration/cli-compat.test.ts