feat: drive reporting/sync + contacts dedupe

[rohan-patnaik]

Summary

• Add Drive reporting commands (tree, du, inventory) with path-based output and size/modified metadata.
• Add Drive sync (pull/push) with dry-run, include/exclude filters, checksum support, delete safeguards, and a local state file.
• Add contacts dedupe with preview/apply workflow and merge rules.
• Add tests and README examples for the new commands.

Testing

• go test ./...

Notes

• Sync state is stored locally in .gog-sync.json (no secrets).
• Google Docs are exported on pull and skipped on push.
• I’m new to OSS contributions — happy to adjust or split this if you prefer.

[visionik]

hi @rohan-patnaik - I like what you've done here, thank you. I'm helping peter get gogcli PR's and issues addressed quickly. Since it's been a while, the merge for this --> main is complex. could you rebase from main and resubmit the PR? Thank you!

[rohan-patnaik]

Rebased onto the latest main and resolved conflicts. Branch is updated and ready for another pass. Thanks!

[visionik]

@rohan-patnaik Looking good. Ci/test would like some lint cleanups:

https://github.com/steipete/gogcli/actions/runs/22588136930/job/65478928149?pr=116

[rohan-patnaik]

Addressed the CI lint cleanup items and pushed an update.

Validation run locally:

• make lint (0 issues)
• go test ./... (all packages passing)

[steipete]

Thanks @rohan-patnaik. I extracted and landed the read-only Drive reporting part of this PR in #554 / e9c496e:

• gog drive tree
• gog drive du
• gog drive inventory

I kept Drive sync and contacts dedupe out of that landing because they have a larger behavioral/risk surface and deserve separate review/live proof. Your authorship is preserved via Co-authored-by and the changelog credits #116. Leaving this PR open for now as the source thread for the remaining sync/dedupe pieces.

[steipete]

Thanks again @rohan-patnaik. I split this up so we could land the safer pieces cleanly on current main:

• Drive reporting (drive tree, drive du, drive inventory) landed in feat(drive): add read-only reporting commands #554 as e9c496e.
• The contacts dedupe idea is now extracted as preview-only gog contacts dedupe in feat(contacts): add dedupe preview #555, with your co-author credit and changelog thanks.

I intentionally did not carry over Drive sync from this PR: bidirectional sync/delete/state behavior needs a separate design and live proof path. Closing this broad/stale PR as superseded by the split PRs rather than leaving the old bundle open.

[steipete]

Superseded by the split landing path: Drive reporting in #554 and contacts dedupe preview in #555. Drive sync remains separate future design work.

[rohan-patnaik]

Thanks @steipete Peter, I appreciate you splitting this up and landing the parts that were ready and thanks for the co-author credit on #554 and #555.

The Drive sync feedback makes sense. I’ll take another pass at that after I have a cleaner live-proof path and a better proposal, instead of trying to keep it bundled into this PR.