[nightly-release] Prepare 1.1.43 candidate notes

[r3dbars]

Summary

• Add release-candidate notes for a possible Transcripted 1.1.43 follow-up.
• Keep version, Sparkle appcast, and Homebrew cask untouched until a real release is approved.
• Call out the latest-release CoreML crash watch item, issue Mic audio recording is a lot quiter #500, and adjacent draft PRs before publication.

Verification

• git diff --check
• bash scripts/release/verify-sparkle-release.sh 1.1.42
• python3 scripts/ops/nightly-security-check.py --write-report build/nightly-security-report.json

No GitHub release was published. No appcast or cask metadata was changed.

[r3dbars]

verdict: no-findings-but-human

findings: none from this pass.
actions: human signoff recommended because this is draft release-candidate positioning and should not imply a real 1.1.43 release until version, appcast, cask, and artifact work are approved.
head_sha: ee9ab6e
fix_commit: none
checks: gh pr view, gh pr diff, release/Sparkle docs read, release-candidate note reviewed for no version/appcast/cask changes, git diff --check origin/main...origin/codex/nightly-release-1.1.43-candidate; GitHub checks reported none.

manual_merge_handoff:
head_sha: ee9ab6e
verdict: no-findings-but-human
blockers: draft PR plus release-candidate/product timing needs human signoff
checks: gh metadata/diff, release docs/static review, diff check