frontend: remove remaining local router.push ignore handlers

[petersutter]

What would you like to be added:
see discussion

Remove the remaining local router.push(...) catch-and-ignore handlers that were originally used to suppress navigation-aborted style outcomes.

Remaining occurrences:

• frontend/src/layouts/GLogin.vue
• frontend/src/views/GShootItemError.vue
• frontend/src/views/GProjectError.vue
• frontend/src/views/GNotFound.vue

Why is this needed:

In Vue Router v4, expected navigation outcomes are already handled centrally in frontend/src/router/index.js via router.afterEach(...failure) and router.onError(...). These local ignore blocks are no longer needed for normal guard redirects and can hide unexpected errors.

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/lifecycle stale

[petersutter]

/remove-lifecycle stale