fix(quick-dev): tighten checkpoint 1 [A] flow wording

- Remove stray 'and options' from the editing-note intro so the note's
  position relative to the [A]/[E] menu is unambiguous.
- Restructure the [A] bullet into explicit missing/exists branches so
  the missing-file HALT cannot fall through to status updates and
  recreate a deleted spec.

Addresses augmentcode review comments on PR #2217.

src/bmm-skills/4-implementation/bmad-quick-dev/step-02-plan.md

@@ -26,13 +26,15 @@ deferred_work_file: '{implementation_artifacts}/deferred-work.md'
 
 Present summary. Display the spec file path as a CWD-relative path (no leading `/`) so it is clickable in the terminal. If token count exceeded 1600 and user chose [K], include the token count and explain why it may be a problem.
 
-After presenting the summary and options, add this note:
+After presenting the summary, add this note:
 
 > The spec is a regular file in your project. Before approving, you can open it in another session and use any tool you like — party mode, advanced elicitation, code review, or direct editing. Take your time; approve when you're satisfied.
 
 HALT and ask human: `[A] Approve` | `[E] Edit`
 
-- **A**: Re-read `{spec_file}` from disk. Compare the content to what you wrote. If the file has changed since you wrote it, acknowledge the external edits — show a brief summary of what changed — and proceed with the updated version. If the file is missing, HALT and tell the user. Set status `ready-for-dev` in `{spec_file}`. Everything inside `<frozen-after-approval>` is now locked — only the human can change it. → Step 3.
+- **A**: Re-read `{spec_file}` from disk.
+  - **If the file is missing:** HALT. Tell the user the spec file is gone and STOP — do not write anything to `{spec_file}`, do not set status, do not proceed to Step 3. Nothing below this point runs.
+  - **If the file exists:** Compare the content to what you wrote. If it has changed since you wrote it, acknowledge the external edits — show a brief summary of what changed — and proceed with the updated version. Then set status `ready-for-dev` in `{spec_file}`. Everything inside `<frozen-after-approval>` is now locked — only the human can change it. → Step 3.
 - **E**: Apply changes, then return to CHECKPOINT 1.