P2: Fix or suppress stale route/link radar findings

[njrini99-code]

Generated by PR #358 route hygiene radar.

Finding group:

• Scanner: scripts/route-hygiene/check-stale-links.mjs
• Count before scanner normalization: 29 P2 candidates

Local report:

• docs/operations/generated/route-stale-link-findings.json

Required remediation:

• Normalize query/hash before route comparison.
• Ignore public asset paths when the files exist.
• Fix remaining truly stale links.
• Re-run npm run routes:check.

[njrini99-code]

Fixed in PR #358 branch: route hygiene now canonicalizes query/hash fragments, ignores existing public assets, and removed the final course-library comment false positive. Validated with npm run routes:check → 0 stale links, 0 duplicate routes, 0 boundary blockers, 0 missing critical routes, 0 dead-route candidates.

[njrini99-code]

Closing as fixed by route-hygiene normalization and the course-library cleanup.