feat(bot): add support for applying labels to bot-created PRs

- Update the publish workflow to read labels from a pr-labels.txt file and apply them to the PR using the gh CLI.
- Update the prs skill to instruct the bot to write labels to pr-labels.txt.
- Update the issue-fixer and metrics skills to explicitly request the application of their respective labels in pr-labels.txt.

.github/workflows/gemini-cli-bot-brain.yml

@@ -375,6 +375,14 @@ jobs:
                 gh pr create --draft --title "🤖 Gemini Bot Productivity Optimizations" --body "Automated changes generated by Gemini CLI Bot." --head "$NEW_BRANCH_NAME" --base main
               fi
             fi
+
+            if [ -s "${{ runner.temp }}/brain-data/pr-labels.txt" ]; then
+              while IFS= read -r label; do
+                if [ -n "$label" ]; then
+                  gh pr edit --add-label "$label" || true
+                fi
+              done < "${{ runner.temp }}/brain-data/pr-labels.txt"
+            fi
           fi
 
       - name: 'Post PR/Issue Comment'