refactor(types): replace untyped any with unknown or specific types

[github-actions]

Closes #311

Applied changes based on Issue #311.

I’ve replaced the remaining untyped any/Promise<any> usages in the core action code:

• In src/github/event.ts, loadEventPayload now returns a Promise<Record<string, unknown>> instead of Promise<any>, and the JSON.parse result is cast to that type.
• In src/github/action.ts, removed the as any cast on runs[0]; the Octokit typings provide the correct shape so we can just use runs[0].
• In src/client/codex.ts, replaced the unsafe (error as any).timedOut cast with a typed interface (error as { timedOut?: boolean }).timedOut.

These changes eliminate untyped any and strengthen the promise return types. Let me know if you’d like to tighten up GitHub payload handling in getEventType (currently still any) or add more specific interfaces!