HEL-8 demo: intentional typecheck regression (DO NOT MERGE)

[lmanualm]

Purpose

Demonstrates that the CI gate configured in HEL-4 + HEL-8 actually blocks merge when CI fails.

This PR introduces a deliberate type error in app/page.tsx (assigning a string literal to a number-typed variable). The typecheck step should fail, the overall ci status check should be failure, and the protected main branch should refuse this merge.

Will be closed without merging once we've captured the failing status.

Test plan

• CI runs on this PR
• install / lint / typecheck / build / smoke reports failure
• Merge button is blocked by branch protection
• PR closed (revert/close) — link captured on HEL-8

[lmanualm]

CI gate confirmed: the install / lint / typecheck / build / smoke check failed as expected (typecheck regression), and branch protection on main blocked the merge. Closing as designed — this was a demo-only PR. See HEL-8 for full acceptance evidence.