Combine API keys into security settings

[arjunkomath]

Summary

• move API key management into the Security settings tab alongside two-factor authentication
• remove the separate API Keys tab and its tab value entirely

Validation

• Oracle reviewed the tab merge; its legacy URL compatibility suggestion was intentionally omitted so the removed tab has no remaining alias
• biome check components/settings/global-settings.tsx
• tsc --noEmit
• git diff --check

[github-actions]

React Doctor found no issues. 🎉

⚠️ Warning: .github/workflows/react-doctor.yml is configured incorrectly. See below to fix.

React Doctor compares against main to report only the issues this pull request introduces. This run couldn't complete that comparison (usually a shallow CI checkout with no merge base), so it listed every issue in the changed files, including ones that already existed on main.

Add fetch-depth: 0 to the actions/checkout step in .github/workflows/react-doctor.yml so the checkout includes the history React Doctor needs:

 jobs:
   react-doctor:
     steps:
       - uses: actions/checkout@v5
+        with:
+          fetch-depth: 0

       - uses: millionco/react-doctor@v2

To silence this warning, set silence-missing-baseline-warning: true on the React Doctor action.

_{Reviewed by React Doctor for commit 12d9996.}