Commonalities warnings (deferred r3.1)

[stroncoso]

Problem description
Per release procedure requirement, all warnings must be documented priori release
-> https://github.com/camaraproject/WebRTC/actions/runs/29228904420

Expected behavior
Fix warnings

• [P-026] Mandatory info.description template missing — 9 hits
• [S-015] Schema name must be PascalCase — 1 hit
• [P-032] Remove API readiness checklist file from API repo — 3 hits

Alternative solution
n/a

Additional context
Automated release procedure

• Release Review: WebRTC r3.1 (rc Sync26) #195