State the .pubignore gap in pub_content_limits precisely - #1902

Summary

• Comment-only: pub_content_limits.dart now says a pub-ignored higher-priority example makes the check size that file and skip the lower-priority one pub.dev shows (Test companion pub content-size check in the release verifier (#1861 sweep 2) #1889 audit item in #1861). Refs 0.19.x audit follow-ups (index) #1861 (tracker not ticked).

Production-readiness scope

• User-facing scope: none; comment edit in release tooling.
• Supported platforms/paths: N/A
• Unsupported or intentionally unavailable paths: N/A
• Out of scope / follow-ups: .pubignore support in the check itself stays unimplemented (no candidate is ignored today).

Completeness checklist

• Declared scope is fully implemented.
• No behaviour change; no changelog.
• Regression coverage: N/A, comment only.
• Security/privacy: N/A

PR type guidance

• Docs-only PR: comment only; no runtime behaviour change.

Test Plan

• dart format --output=none --set-exit-if-changed .
• Others: N/A, comment only

Matrix Evidence

Review Notes

• Independent review status: pending; classified high-risk only because the path is release automation
• CI status / head SHA: see checks

High-risk regression review

• Classification: high-risk (releaseAutomation, comment-only)
• Implementation task: lane 1861c
• Independent blocking QA task: pending
• Exact head / current base: pending
• Production-branch deletion, bypass, or miswire proof: N/A, comment only
• Affected-family real-model/artifact evidence: N/A
• Explicit unavailable-family or other N/A evidence: N/A
• Known PR-caused P1 regressions: 0
• Unresolved review threads: 0