fix(sdk): handle Codex MCP elicitation requests

[ross-rl]

Summary

• classify and route mcpServer/elicitation/request as a typed Codex server request
• safely cancel unattended elicitations and round-trip structured handler responses
• treat serverRequest/resolved as terminal during live handling and Axon replay
• expose an abort signal so applications can clear parked UI state
• document the recovery boundary: client reconnect is replay-safe while Codex lives, but Codex process restart requires durably reissuing the operation

Reproduction trace

Built against the deterministic broker functional trace in runloopai/runloop#10790. The trace directly invokes an MCP tool whose server sends elicitation/create, producing:

{"method":"mcpServer/elicitation/request","id":0,"params":{"mode":"form","message":"Which city should the test use?","requestedSchema":{"type":"object","properties":{"city":{"type":"string"}},"required":["city"]}}}

Tests

• bun run check
• bun run typecheck
• bun run build
• bun run test (25 files, 586 tests)