docs(blog): draft macos screen narrator post

[solrevdev]

Summary

• Add draft blog post for macos-screen-narrator with current site tone/format
• Explain the local prep/render workflow for narrated macOS screen recordings
• Cover FFmpeg/ffprobe analysis, LLM-timed segment JSON, and macOS say rendering
• Add draft cover image
• Keep as draft with published: false

Follow-up checklist (for when picking this up next)

1. Move repo from dated staging folder into Projects:
   • Rename/copy the tool repo to its final project directory
   • Confirm generated work folders and local-only artifacts stay ignored
2. Set git remote to match blog URL:
   • git remote -v
   • git remote remove origin (if needed)
   • git remote add origin https://github.com/solrevdev/solrevdev.macos-screen-narrator.git
3. Configure auth + NuGet publishing secret:
   • gh auth login
   • Create NuGet API key on nuget.org
   • Add repo secret NUGET_API_KEY
   • Ensure workflow uses it for dotnet nuget push
4. Push + merge flow:
   • Push branch in tool repo
   • Open PR and merge to master (or chosen publish branch)
5. Make blog post live at publish time:
   • Set published: true
   • Rename post file date prefix and/or set front matter date: to actual publish date/time
   • Note permalink date changes if date is changed

Notes

• This PR is intentionally a draft content PR for review and timing.
• Sensitive source-folder and generated-work naming has been excluded from the post and PR text.

Validation

• dotnet test in the tool repo: passed, 7 tests
• Sensitive-term scan on new post and cover image: no hits
• bundle exec jekyll build: blocked because required gems were missing
• bundle install: blocked by nokogiri 1.13.10 native extension build failure on Ruby 3.4.1