Autofix: single opt-in path from Post-CI; retire duplicate Autofix entry point

[github-actions]

Topic GUID: be3ef56d-f2ef-54f5-8c16-0b7d379bdfb1

Why

You have two places that try to “do small hygiene fixes.” That’s how you get mysterious commits and finger-pointing. Make Post-CI the only invoker of the reusable autofix and delete the standalone PR autofix workflow, or vice versa. Pick one brain.
GitHub

Task List:

Wire maint-46-post-ci.yml to call the reusable autofix job only when the PR has autofix (and optionally autofix:clean).

Remove the separate Autofix workflow file that duplicates behavior.

Normalize the label name in code and docs to one string (autofix:clean recommended) and drop fallbacks.

Post a concise summary comment listing files touched and checks re-run.

Tasks

Not provided.

Acceptance criteria

Exactly one workflow path can perform autofix in PRs.

The chosen path is gated by an opt-in label and produces a single summarizing comment.

No duplicate “fix” commits for the same PR event.

Implementation notes

Use workflow_call with explicit inputs for dry-run and allowed file globs.

Keep the diff surface intentionally small: formatting, trivial lints, import order.

---

Synced by workflow run.

[stranske]

Opened PR #2891 to engage Codex. Track work there.

[github-actions]

Opened PR #2891 to engage Codex.

Comment with @codex start, then paste the helper text so Codex produces a keepalive-ready brief and checklist in its first reply.

@codex start

Codex, begin by posting a single Markdown comment in this PR that includes:
- A **Scope / key constraints** section
- An **Acceptance criteria / definition of done** section
- A **Work plan** section containing exactly seven outstanding tasks formatted as `- [ ] Task description` (leave them unchecked so keepalive can monitor progress)

After you publish that comment, continue with your normal planning file updates and implementation work.

Issue context (optional: copy into the PR body if needed):

### Source Issue #2883: Autofix: single opt-in path from Post-CI; retire duplicate Autofix entry point

Source: https://github.com/stranske/Trend_Model_Project/issues/2883

> Topic GUID: be3ef56d-f2ef-54f5-8c16-0b7d379bdfb1
> 
> ## Why
> You have two places that try to “do small hygiene fixes.” That’s how you get mysterious commits and finger-pointing. Make Post-CI the only invoker of the reusable autofix and delete the standalone PR autofix workflow, or vice versa. Pick one brain. 
> GitHub
> 
> Task List:
> 
> Wire maint-46-post-ci.yml to call the reusable autofix job only when the PR has autofix (and optionally autofix:clean).
> 
> Remove the separate Autofix workflow file that duplicates behavior.
> 
> Normalize the label name in code and docs to one string (autofix:clean recommended) and drop fallbacks.
> 
> Post a concise summary comment listing files touched and checks re-run.
> 
> ## Tasks
> _Not provided._
> 
> ## Acceptance criteria
> Exactly one workflow path can perform autofix in PRs.
> 
> The chosen path is gated by an opt-in label and produces a single summarizing comment.
> 
> No duplicate “fix” commits for the same PR event.
> 
> ## Implementation notes
> Use workflow_call with explicit inputs for dry-run and allowed file globs.
> 
> Keep the diff surface intentionally small: formatting, trivial lints, import order.
> 
> ---
> Synced by [workflow run](https://github.com/stranske/Trend_Model_Project/actions/runs/18646450557).