Fix workflow config gaps: enable @nohwnd mentions, fix PR description instruction (#15770)

- daily-qa: Enable mentions and allow @nohwnd reference so digest notifications work
- pr-iteration: Change PR description instruction from 'rewrite it' to 'flag in comment' (workflow lacks write permission to update PR body)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: nohwnd

.github/workflows/daily-qa.lock.yml

@@ -23,8 +23,8 @@ imports:
 safe-outputs:
   noop:
     report-as-issue: false
-  mentions: false
-  allowed-github-references: []
+  mentions: true
+  allowed-github-references: ["@nohwnd"]
   create-issue:
     max: 1
     title-prefix: "Daily Maintenance Digest"

.github/workflows/daily-qa.md

@@ -90,7 +90,7 @@ If triggered by `schedule` or `workflow_dispatch`, check ALL your PRs and iterat
    d. Make the requested changes
    e. Build and run tests to verify
    f. Push the fix
-   g. Verify the PR description accurately describes the code changes. If it's a template placeholder or doesn't match the diff, rewrite it.
+   g. Verify the PR description accurately describes the code changes. If it's a template placeholder or doesn't match the diff, flag it in a review comment with a suggested replacement description.
    h. Reply briefly to the review comment confirming what you changed
 4. If the comment is just a question or discussion, reply if you can add useful context. Otherwise noop.
 
@@ -104,7 +104,7 @@ If triggered by `schedule` or `workflow_dispatch`, check ALL your PRs and iterat
       - Determine if it's a code issue (fix it) or infrastructure flake (comment and skip)
       - Push a fix if possible
    c. Check for unaddressed review comments. If any, address them.
-   d. Check that the PR description accurately describes the code changes. If it's a template placeholder or doesn't match the diff, rewrite it.
+   d. Check that the PR description accurately describes the code changes. If it's a template placeholder or doesn't match the diff, flag it in a comment with a suggested replacement description.
    e. Check for merge conflicts. If conflicted, merge main and push.
 3. Update cache-memory with the cleaned-up list (remove merged/closed PRs).