Introduce delay and expand path matching on Backoffice router for lazy-loaded routes

[nielslyngsoe]

The cases described here fixes an issue that only appeared on an actual server. these can be seen on a local server by running with disabled cache and a network throttling like this:

This fixes two things:
A.
Fixes so a deep link does not just redirect to the root of a section, typically section/settings — this is resolved by using pathMatch 'full', a feature of the router slot we have not utilized previously.

B.
Fixes so the initial empty path load does not go to section/settings, just because it loaded slightly before the content section. This is done by introducing a feature that makes redirects await a delay, the delay will be reset everytime a new route appears, making it able to extend the time as long as routes are getting registered within the given delay. And then the delay is calculated based on the browsers assumption on the internet speed. That's a guess but better than none.

[Copilot]

Pull Request Overview

This PR enhances route redirects by enforcing full path matching on default routes and introduces a delay mechanism for initial redirects to ensure all routes register before navigation.

• Add pathMatch: 'full' to empty-path redirects to prevent unintended root fallback.
• Implement awaitStability with a network-based delay in RouterSlot for initial redirect timing.
• Extend the redirect model (IRedirectRoute) to include the optional awaitStability flag.

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
created-packages-section-view.element.ts	Added pathMatch: 'full' to default redirect.
member-workspace-editor.element.ts	Added pathMatch: 'full' to default redirect.
media-workspace-editor.element.ts	Added pathMatch: 'full' to default redirect.
media-dashboard.element.ts	Added pathMatch: 'full' to default redirect.
document-blueprint-workspace-editor.element.ts	Added pathMatch: 'full' to default redirect.
content-editor.element.ts	Added pathMatch: 'full' to default redirect.
content-type-design-editor.element.ts	Added pathMatch: 'full' to default redirect.
block-workspace-view-edit.element.ts	Added pathMatch: 'full' to default redirect.
backoffice-main.element.ts	Added pathMatch: 'full' and awaitStability: true to initial redirect.
router-slot.ts	Added getRedirectDelay() and delay logic around awaitStability.
model.ts	Extended IRedirectRoute with awaitStability?.
example-modal.element.ts	Added pathMatch: 'full' to default redirect in modal example.
dashboard.element.ts	Added pathMatch: 'full' to default redirect in dashboard example.

Comments suppressed due to low confidence (1)

src/Umbraco.Web.UI.Client/src/packages/core/router/router-slot/router-slot.ts:408

• Add unit tests for the awaitStability logic to verify that redirects are correctly delayed and canceled when navigation is invalidated.

if (route.awaitStability === true) {