[codex] complete cron and swap labs

[HimanM]

Description

Completes the existing cron-broken and swap-broken lab scenarios by adding the required solution.sh files so CI can automatically fix and verify them.

These solution scripts are required for the lab verification pipeline, and the repository's post-merge workflow removes solution.sh files from main after merge.

Type of change

• Bug fix
• New feature
• New Lab

Lab Requirements (If submitting a new lab)

If you are submitting a new BrokenOps lab, please verify:

• The lab.yaml is fully populated.
• The cloud-init.yaml correctly breaks the environment.
• The verify.sh script correctly asserts if the environment is fixed.
• The solution.md provides the step-by-step solution to fix the environment.
• The question.md provides the question for the lab.
• Follows the LAB_FORMAT.md guidelines.
• MANDATORY: A working solution.sh script is provided to automatically fix the environment. (This is required for our CI verification pipeline).

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas

Closes Issues ?

• closes issue [LAB IDEA] Cron Job Never Executes #38
• closes issue [LAB IDEA] Swap File Not Persistent #46

Validation

• bash -n labs/cron-broken/solution.sh labs/swap-broken/solution.sh
• git diff --check