Summary

• add mutually exclusive --url sources to slides insert-image and slides replace-slide
• require explicit URL dimensions for insertion instead of fetching remote content locally
• bypass Drive upload/public-sharing services entirely for URL sources
• preserve the existing positional local-file flow and improve failed temp-file cleanup reporting
• update generated command docs and changelog

Closes #825.

Testing

• go test ./internal/cmd -run 'Test(ResolveSlidesImageSource|SlidesInsertImage|SlidesReplaceSlide)' -count=1
• make ci
• /Users/steipete/Projects/agent-skills/skills/autoreview/scripts/autoreview --mode local --stream-engine-output (clean after fixing its accepted path-preservation finding)
• live Google Slides E2E with the designated Clawdbot test OAuth account:
  • created a temporary presentation
  • inserted the README banner through a public HTTPS URL
  • read the slide back and verified the returned image object
  • replaced it through a second public HTTPS URL
  • polled read-back until the same object ID exposed changed cached content
  • moved the temporary presentation to Trash and verified trashed=true

Caveat

The live account permits Drive sharing, so it cannot reproduce the tenant policy error itself. Unit tests prove both URL commands never initialize Drive, while the live test proves Google Slides accepts and caches the direct URL requests.