#133 feat(settings): move Desktop downloads under Settings > Workspace

What

Product ask: no dedicated Downloads tab; put downloads under the Workspace settings.

• Nav: the top-level Downloads item is gone from the workspace nav. Sessions and the rest are unchanged.
• Settings > Workspace: the Desktop downloads now render as a card ("Download ") directly below Connect your agents. It keeps everything the Downloads page had: the release/channel picker, the recommended download for the detected OS, all per-OS installers with version and checksums, and the command-line install. The Workspace tab is not admin-only, so members still see downloads, as before.
• Old links: #/downloads and the /downloads path still work. They render Settings > Workspace and rewrite the URL to #/settings/workspace with replaceState, so the back button isn't polluted. Deep links and docs that use them keep working.

Tests

• downloads.test.tsx: all existing downloads behaviour now runs on the embedded DesktopDownloads component. A test checks the nav has no Downloads link, and another that the card is a titled region.
• admin.test.tsx: the retired #/downloads link lands on Settings > Workspace with the downloads card, the URL becomes #/settings/workspace, and there is no Downloads nav link.

npm run check is green locally (58 files, 907 tests).

🤖 Generated with Claude Code

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