fix: add mandatory compile checkpoint gate in Step 13 (Schedule It) (#1349)

Author: Copilot

workshop/13-schedule-it.md

@@ -38,6 +38,7 @@ Both paths update the same fuzzy schedule expression and finish by confirming it
 
 After completing your chosen path, verify:
 
+- [ ] I ran `gh aw compile` after editing the schedule expression and confirmed the lock file updated.
 - [ ] I can explain what a `schedule:` trigger does in GitHub Actions — it runs the workflow automatically at the defined cadence without manual intervention.
 - [ ] I understand that `gh aw compile` converts a fuzzy expression like `daily on weekdays` into a valid cron string in the lock file.
 - [ ] The `schedule:` field in `.github/workflows/daily-status.md` contains a valid schedule expression (for example, `daily on weekdays`).

workshop/13a-schedule-it-terminal.md

@@ -65,6 +65,9 @@ on:
 
 ### Compile and validate
 
+> [!IMPORTANT]
+> Run `gh aw compile` after editing the schedule — this is required before committing.
+
 ```bash
 gh aw compile
 ```

workshop/13b-schedule-it-ui.md

@@ -36,8 +36,8 @@ You'll update the fuzzy schedule expression in the GitHub web editor, commit it,
 
 Keep `workflow_dispatch` so you can still run the workflow on demand.
 
-> [!NOTE]
-> The GitHub UI path skips local compile checkpoints. GitHub Actions compiles the change and reports syntax errors in the run log.
+> [!IMPORTANT]
+> Committing the `.md` file via the web editor does **not** automatically recompile the lock file. After committing, open your Codespace or local terminal and run `gh aw compile`, then push the updated `.lock.yml`.
 
 <!-- Separate adjacent callouts -->