feat(drive): add changes tracking for sync and automation (Changes API v3)

[dl-alexandre]

Summary

Add support for Google Drive Changes API v3 to enable sync tools, incremental backups, and real-time change monitoring.

Current State

gog drive supports file operations (ls, search, upload, download, etc.) but has no mechanism to track changes over time. Users must poll or maintain external state to detect modifications.

Proposed Commands

gog drive changes start-token                    # Get starting page token
gog drive changes list --token <token>           # List changes since token
gog drive changes list --token <token> --max 50  # With pagination
gog drive changes watch --token <token> --webhook-url <url>  # Set up webhook
gog drive changes stop <channelId> <resourceId>  # Stop webhook

Use Cases

• Build sync tools that mirror Drive to local storage
• Incremental backup systems that only fetch changed files
• Automation workflows triggered by file changes
• Real-time monitoring for compliance/security

API Notes

• API: https://developers.google.com/drive/api/v3/reference/changes
• Scopes: Standard Drive scope (no additional scopes required)
• The Changes API provides page tokens for resumable change tracking

Related

None — this is a new capability.

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I've implemented this in another Drive CLI and can share implementation details if helpful.

[salmonumbrella]

@dl-alexandre great idea. Can you please open a PR for this?

[steipete]

Fixed on main in fc7c536 (with final CI/lint cleanup through 57080af).

Added gog drive changes start-token, list, watch, and stop, using Drive API v3 Changes/Channels, with paging/shared-drive options, tests, generated command docs, README docs, and changelog.

Live proof: fetched a start page token and listed changes for the test account (changes: 0, nextPageToken returned), proving auth and endpoint wiring. CI is green on main: 25601394551.