docs(user-guide): document cloud scoped vs classic atlassian token urls

[kostiantyn-pshenychnyi1]

Summary

Documents why Atlassian Cloud Jira/Confluence integrations fail when a scoped API token is used with the site URL. Since CodeMie sends requests to exactly the URL provided, the URL must match the token type. This closes the gap that led users to enter https://<domain>.atlassian.net (or .../jira) with a scoped token and get authentication failures.

Ref: EPMCDME-13642

Changes

• jira.mdx — clarified the URL field for Cloud (classic vs scoped token) and added a warning explaining scoped tokens require the https://api.atlassian.com/ex/jira/<cloud-id> gateway, with cloud-ID lookup via /_edge/tenant_info.
• confluence.mdx — same clarification for Confluence (https://api.atlassian.com/ex/confluence/<cloud-id>).
• FAQ — added why-does-my-cloud-jira-or-confluence-integration-fail-with-a-scoped-token.md.
• Self-hosted (Server/Data Center) guidance left unchanged: scoped tokens are Cloud-only, so those instances always use the site URL.

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 (npm run build succeeds)
• No raw angle brackets
• Sidebar references document IDs (no new pages added)
• Images stored locally next to content
• Commit messages follow Conventional Commits
• No secrets or credentials in documentation (verified with Gitleaks — no leaks found)