[Fix] Deleted-line review threads lose anchors and runtime OAuth providers stay connected

[roomote-roomote]

Opened on behalf of Matt Rubens. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Preserve old-side line anchors when reading Bitbucket comments created with inline.from and Azure DevOps threads created with leftFileStart.
• Treat persisted GitLab, Gitea, and Bitbucket OAuth connections as removable state even when provider client credentials come only from runtime configuration.
• Add regression coverage and patch changesets for both fixes.

Why this change was made

Review feedback on the v0.35.0 promotion found that deleted-line comments lost their anchors on later reads and that runtime-configured OAuth providers could return before persisted connection cleanup ran.

Impact

Later reviews can match and reply to existing deleted-line threads on Bitbucket and Azure DevOps. Administrators can fully disconnect runtime-configured GitLab, Gitea, and Bitbucket providers, including hook cleanup, OAuth token removal, and repository deactivation.

Focused tests, type checks, formatting, and changed-file lint pass. The full SDK lint remains blocked by two pre-existing unused eslint-disable warnings outside this diff.

Related PRs

• Review feedback originated from Promote v0.35.0 to production.

[roomote-community]

No code issues found. See task

_{Reviewed 72b9c76}