docs: make the training exercise safe to fork

[ibloud]

Summary

Adds the missing permissions and safeguards for self-directed learners and fan forks.

• applies MIT to software, tests, configuration, and code examples
• applies CC BY-NC-SA 4.0 to curriculum, instructions, scoring material, narrative, and documentation
• reserves Loptr Lab branding and prohibits implied official evaluation or endorsement
• warns against submitting personal, disability, workforce, education, or employment records
• preserves the noncanonical training boundary
• adds CI that accepts the intentional starter placeholders but requires real tests to pass after implementation begins

No candidate contract, scoring test, or game canon is changed.