[feat] View as another user profile on the profile page

[cenodude]

Problem to solve

• The Main page has a profile selector, but the profile page and its tabs ignore it
• Admins cannot quickly see what a user has in Watchlist, History, Ratings, Collections or Progress
• The profile page could show one profile in the Overview widgets and another in the tabs

Proposal

• Add a View as picker for admins in the profile header, shared with the Main selector
• Support a direct link: /profile?as=
• Every tab and the media modal only show data from that profile's provider accounts
• Show a banner with Back to my profile
• Keep it read-only: no Settings tab, no bulk remove, no Progress actions, no avatar upload
• No login-as or session swap, the server already limits this to admins

Area

• Watchlist
• Ratings
• History
• Playlists
• Scrobble watcher
• Scrobble webhook
• Scheduler
• Analyzer, Events, Exporter
• Web UI
• Command line interface
• Config/API

[cenodude]

ghcr.io/cenodude/crosswatch-dev:dev-db