feat(omo-codex): add start-work continuation component

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

packages/omo-codex/plugin/components/start-work-continuation/src/index.ts

@@ -0,0 +1,5 @@
+export type { ContinuationState, PlanChecklist } from "./boulder-reader.js";
+export { parsePlanChecklist, readContinuationState } from "./boulder-reader.js";
+export { runStopHook } from "./codex-hook.js";
+export { START_WORK_CONTINUATION_DIRECTIVE } from "./directive.js";
+export type { ReadonlyFileSystem, StopHookEventName, StopHookOutput, StopInput } from "./types.js";