fix(gmail): archive complete threads explicitly

[steipete]

Summary

• add explicit gmail archive --thread <threadId>... semantics using Gmail users.threads.modify
• preserve existing positional message-ID and --query behavior unless --thread is set
• reject ambiguous --thread --query combinations before auth
• continue across per-thread API failures, emit retry-safe per-thread JSON/plain results, then return nonzero for partial failure
• update generated command docs and changelog

Closes #752.

Verification

• focused archive dry-run, API request, normalization, query-conflict, success-output, and partial-failure tests
• full make ci (629 generated command pages, 23 feature pages)
• structured autoreview: clean after adding retry-safe partial-failure reporting
• live Gmail E2E with clawdbot@gmail.com and sending disabled:
  • selected an existing two-message test thread with no INBOX labels
  • added INBOX to the whole thread and verified both messages entered the inbox
  • ran gmail archive --thread; verified both messages lost INBOX
  • verified JSON count/failure/result fields
  • verified final message labels exactly matched the original state

CLI contract

--thread applies only to positional IDs. Gmail message and thread IDs are opaque, so the command does not guess their type. --query retains message-level semantics.

Risk

Low/medium. The behavior is additive and explicit. Multiple thread API calls are not atomic; partial outcomes are fully reported and the command exits nonzero when any thread fails.

[steipete]

Landed as 3f653c7.

Proof:

• focused dry-run, normalization, API request, query-conflict, success, and partial-failure tests pass
• full make ci pass; 629 generated command pages and 23 feature pages
• autoreview found partial-failure retry ambiguity; fixed with per-thread continuation/results and nonzero summary; final autoreview clean
• exact-head CI green on duplicate Linux, Windows, Darwin/cgo, worker, and Docker checks; one hung Windows runner was cancelled and rerun successfully
• live Gmail E2E with sending disabled: added INBOX to both messages in an existing two-message test thread, gmail archive --thread removed it from both, JSON reported success, and final labels exactly matched the original state