[app-server] feat: add Declined status for command exec

[owenlin0]

Add a Declined status for when we request an approval from the user and the user declines. This allows us to distinguish from commands that actually ran, but failed.

This behaves similarly to apply_patch / FileChange, which does the same thing.

[owenlin0]

@codex review this

[chatgpt-codex-connector]

💡 Codex Review

codex/codex-rs/app-server-protocol/src/protocol/v2.rs

Lines 858 to 862 in e0ce5ac

	pub enum CommandExecutionStatus {
	InProgress,
	Completed,
	Failed,
	Declined,

Update TS types for declined command status

Command executions can now complete with a Declined status when the user rejects an approval request (see new enum variant added here), but the TypeScript SDK still constrains CommandExecutionStatus to "in_progress" | "completed" | "failed" (sdk/typescript/src/items.ts:6). Any v2 client consuming these notifications through the SDK will now see type errors or unhandled values when a command is declined. The SDK’s union should be extended to include "declined" so clients can safely process the new status.

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".