🤖 fix: resolve Codex threads before pushing in skill docs (#13)

## Summary
Align the Codex comment-handling instructions so agents resolve Codex
review threads before pushing fixes.

## Background
`AGENTS.md` already required resolving threads before push, but one
numbered list in `.mux/skills/pull-requests/SKILL.md` had the reverse
order. This mismatch could lead agents to push before thread resolution.

## Implementation
- Updated the **Handling Codex Comments** sequence in
`.mux/skills/pull-requests/SKILL.md` to explicitly require resolving
each thread before pushing.
- Kept the rest of the review loop and readiness criteria unchanged.

## Validation
- `make verify-vendor`
- `make test`
- `make build`

## Risks
Low risk. This is a documentation-only sequencing fix in agent guidance.

---
_Generated with [`mux`](https://github.com/coder/mux) • Model:
`openai:gpt-5.3-codex` • Thinking: `xhigh` • Cost: `$0.12`_

<!-- mux-attribution: model=openai:gpt-5.3-codex thinking=xhigh
costs=0.12 -->

Author: ThomasK33

.mux/skills/pull-requests/SKILL.md

@@ -74,10 +74,11 @@ Use these scripts to check, resolve, and wait on Codex review comments:
 
 When Codex leaves review comments, you **must** address them before the PR can merge:
 
-1. Push your fixes
-2. Resolve each review thread: `./scripts/resolve_pr_comment.sh <thread_id>`
-3. Comment `@codex review` to re-request review
-4. Run `./scripts/wait_pr_codex.sh <pr_number>` to wait for the next Codex response (either new comments to address, or an explicit approval comment)
+1. Address the feedback in your branch.
+2. Resolve each review thread before pushing: `./scripts/resolve_pr_comment.sh <thread_id>`
+3. Push your fixes.
+4. Comment `@codex review` to re-request review.
+5. Run `./scripts/wait_pr_codex.sh <pr_number>` to wait for the next Codex response (either new comments to address, or an explicit approval comment).
 
 ### Required Loop Discipline