docs(user-guide): add per-user oauth 2.0 sign-in for gitlab, jira, and confluence

[batyrkhanmekin-glitch]

Summary

Documents the per-user OAuth 2.0 sign-in flow for GitLab, Jira, and Confluence integrations (EPMCDME-13527). An administrator configures the OAuth application once; each member then authorizes under their own account so tokens are per-user — nobody borrows another member's token.

Changes

• Updated jira.mdx and confluence.mdx with tabbed PAT / OAuth 2.0 integration setup and a new "Connect from Chat" section for the in-chat connect gate
• Updated git-github-gitlab-bitbucket.md with a GitLab OAuth 2.0 authentication tab and in-chat connect section; feature-flag visibility note (GITLAB_OAUTH_ENABLED)
• Added docs/admin/configuration/oauth-integrations.md — admin guide covering provider enable flags, GitLab OAuth app registration, Atlassian OAuth app registration (shared for Jira + Confluence), env vars, and troubleshooting table
• Added OAuth info admonition to tools/overview.md and FeatureCard to admin configuration index
• Added FAQ entry: "How do I connect my GitLab/Jira/Confluence account to a shared OAuth integration?"

Testing

• Tested locally with npm start
• All pages render correctly
• Images display properly
• Internal links work
• Sidebar navigation works

Quality Checks

• npm run check passes (typecheck + lint + commitlint)
• No MDX compilation errors
• No raw angle brackets
• Sidebar references document IDs (not filenames)
• Images stored locally next to content
• Commit messages follow Conventional Commits
• No secrets or credentials in documentation

Additional Notes

Screenshots for the new OAuth sections are pending capture. Placeholder filenames for when screenshots are added:

• jira-oauth-integration-form.png, jira-chat-auth-prompt.png
• confluence-oauth-integration-form.png, confluence-chat-auth-prompt.png
• git-gitlab-oauth-integration-form.png, git-gitlab-chat-auth-prompt.png

[github-actions]

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[elluvium]

Not sure that we require a new visual tile just for this page. Also there's a special doc page with API configuration Please move it also there

[batyrkhanmekin-glitch]

configuration, this page is not accessible for me. Can you please give me permission or share some other needed details

[batyrkhanmekin-glitch]

fixed

[codemie-ai]

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