docs: focus user guides on features and workflows

User guides had accumulated descriptions of visible controls and individual UI states. Rewrite them around major features, setup, and behavior users need explained, and consolidate overlapping theme and tool-activity guidance.

Keep provider setup, account switching, remote access, permissions, and troubleshooting, with a complete user-guide index.
8ec6a67477Julius Marminge committed on 9/4/2026, 7:36:33 PMparent33a9aae
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