v0.321.0: FileBrowser's stale password and its own banners; one backup section on the Data tab; install address of an installed app

R-1101: the change-it line is gone for FileBrowser; in the generated state the page asks FileBrowser whether
the stored password still logs in (only its own 401/403 counts) and, refused, says so and offers the
new-password press. The rendered FileBrowser config switches off its update notice and its Install-app
prompt. The Data tab's backup part is one section in plain words (no off-drive, no PBS); the export
password eye is a text button. R-1095: /apps/{slug}/install of an installed app 302s to its settings tab.

Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/server.go

@@ -112,6 +112,8 @@ type Server struct {
 	syncFileBrowserHook func()
 	// presentDrivesFn replaces the stack manager's PresentMediaDrives in tests (the app page's folder links, v0.320.0).
 	presentDrivesFn func() []string
+	// fbStoredRefused replaces the FileBrowser stored-password check in tests (R-1101, v0.321.0).
+	fbStoredRefused func() bool
 	// langSwitchSync replaces the language switch's file-browser sync in tests (R-691).
 	langSwitchSync func()