Deprecation notice links to malformed hooks docs URL (`/codex/hooks.` returns 404)

What issue are you seeing?

A user-facing deprecation notice currently points to a malformed hooks documentation URL with a trailing period:

https://developers.openai.com/codex/hooks.

That exact URL returns 404, so the notice sends users to a broken page instead of the hooks docs.

I found the malformed URL in the runtime deprecation notice string here:

• codex-rs/core/src/session/session.rs

The same malformed URL is mirrored in the regression test expectation here:

• codex-rs/core/tests/suite/deprecation_notice.rs

What steps can reproduce the bug?

1. Configure the deprecated notify setting so Codex emits the deprecation notice. For example:

notify = ["notify-send", "Codex"]

1. Start Codex so it loads the config and emits the warning.
2. Observe the deprecation details text:

Switch to a `Stop` hook for end-of-turn automation. See https://developers.openai.com/codex/hooks.

1. Open or copy the URL exactly as shown.
2. Actual result: https://developers.openai.com/codex/hooks. returns 404 because the trailing period is treated as part of the URL.

Independent verification from the repo side:

• codex-rs/core/src/session/session.rs:588 contains the malformed URL in the emitted notice.
• codex-rs/core/tests/suite/deprecation_notice.rs:144 asserts the same malformed URL.

What is the expected behavior?

The deprecation notice should link to the real hooks documentation URL without trailing punctuation:

https://developers.openai.com/codex/hooks

Additional information

This looks like a narrow repo-owned fix:

• update the deprecation notice string in codex-rs/core/src/session/session.rs
• update the matching assertion in codex-rs/core/tests/suite/deprecation_notice.rs

I also checked for duplicates before filing and did not find an existing issue specifically tracking this malformed hooks URL.

If this scope matches maintainers' intent, I can prepare a focused fix branch and open a PR if invited under the repo's contribution policy.