fix: complete post-merge API migrations

[kixelated]

Summary

• pass the catalog video priority in the stale moq-video discontinuity test
• restore UniFFI defaults for optional video hint fields that were lost when main merged into dev
• update the Python defaults regression to the renamed PCM format and max-age fields
• expose and test the Go ErrUnresolvableBroadcast sentinel using the current vanity module paths

The dev merge combined the new regression tests with older conflict resolutions in their implementations and wrappers, leaving the full-tree Check gate unable to compile or type-check.

Public API changes

• Go adds the missing additive ErrUnresolvableBroadcast sentinel for the existing FFI error variant.
• UniFFI-generated constructors once again default every optional MoqVideoHint field to None, matching main and the intended API.

Wire behavior changes

None.

Test plan

• just fix
• just check-all through the final Go gate
• just go check after correcting the stale test import paths

Cross-package sync: Rust FFI, Python, and Go are updated together. Kotlin generation and tests passed in check-all; Swift was skipped locally because no Swift toolchain is available.

(written by GPT-5)

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-01T17:52:24.395253Z	62c26b7	New commits

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