Triage MathModDB internal error and add fork-hotfix effort estimate for WikibaseLocalMedia

[Copilot]

The reported backend failures for Item:Q6830616 and Item:Q6830767 are runtime ArgumentCountError exceptions in WikibaseLocalMedia (File::getDimensionsString() signature mismatch after MediaWiki upgrade), while corresponding frontend pages render normally.
This PR addresses the immediate roadmap need by recording a concrete, execution-ready estimate for a fallback fork-based fix path if upstream is not delivered in time.

• Issue diagnosis captured

  • Confirms root cause from debugging context: incompatibility between current MediaWiki version and WikibaseLocalMedia call site.

• Delivery planning unblocked

  • Added a scoped engineering estimate in-thread for implementing and deploying an internal compatibility hotfix fork.

• Proposed fallback scope (documented)

  • Hotfix implementation for API-signature compatibility guard.
  • Focused staging validation on affected item pages + adjacent media cases.
  • Release/deploy and rollback buffer.

Estimated fork workaround effort: ~0.5–1 engineer day
- Hotfix implementation: 1–2h
- Compatibility validation: 2–3h
- Release/deploy: 1–2h
- Buffer/rollback prep: ~1h