fix(fe): Reset identity popover state on authentication failure

[sea-snake]

When switching identities via the identity popover, if authentication fails
(e.g. the user cancels the passkey prompt), the popover and dialog state
(isIdentityPopoverOpen, isAuthDialogOpen, isAuthenticating) are never
reset. This leaves the UI in a broken state where the popover cannot be closed by clicking outside it.

Changes

• Wrap handleSignIn in try/finally blocks across three routes so that
  popover/dialog state is always cleaned up, even when authentication throws:
  • (channel)/authorize/+layout.svelte
  • +page.svelte
  • manage/(authenticated)/+layout.svelte

[Copilot]

Pull request overview

This PR ensures the identity switcher UI doesn’t get stuck in an “authenticating” state when authentication is cancelled or otherwise fails, by guaranteeing popover/dialog state cleanup even when authenticate(...) throws.

Changes:

• Wrapped handleSignIn in try/finally so isIdentityPopoverOpen, isAuthDialogOpen, and isAuthenticating are always reset.
• Applied the same cleanup pattern across the landing page, authorize layout, and manage authenticated layout.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/frontend/src/routes/(new-styling)/manage/(authenticated)/+layout.svelte	Ensures identity popover/auth dialog state is reset even if sign-in throws during identity switching.
src/frontend/src/routes/(new-styling)/+page.svelte	Adds try/finally cleanup around sign-in/navigation so the landing page identity switch UI can’t get stuck.
src/frontend/src/routes/(new-styling)/(channel)/authorize/+layout.svelte	Ensures authorize flow identity switching resets UI state on authentication failure/cancellation.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.