refactor(fe): replace route-based authorize views with store-driven rendering

[sea-snake]

The authorize flow previously used three route groups with child routes to render different views — making the flow scattered and hard to follow. Users navigated between /authorize, /authorize/continue, and /authorize/upgrade-success, with separate routes for OpenID init and resume flows.

This PR consolidates everything into a single /authorize route. URL search params (?openid=<issuer>, ?flow=openid-resume) determine the channel establishment mode, and store state drives which view renders — no more child route navigation.

Changes

• Single /authorize route replaces three route groups. (channel), (pending-channel), and (resuming-channel) are deleted. One layout handles all channel modes based on URL params.
• Store-driven view selection. The page renders views based on store state priority: authorized → redirect animation, OpenID resume processing → redirect animation, upgrade success → countdown, selected identity → account selection, default → auth wizard.
• Extracted view components. AuthWizardView, ContinueView, UpgradeSuccessView, and RedirectAnimationView are co-located with the route under authorize/views/.
• Unified redirect animation. The animated SVG progress screen from the OpenID resume flow replaces the old ProgressRing redirect screen, with a breathing pulse after the draw completes and a 10s fallback dialog.
• Promise-based authorization. authorize() accepts Promise<bigint | undefined> so the redirect animation can start immediately while account resolution continues in the background.
• Views use props instead of store access. ContinueView and UpgradeSuccessView receive effectiveOrigin and onAuthorize as props rather than importing authorization stores directly.
• OpenID init logic inlined. The redirect-to-provider logic runs in onMount — no separate component for something that doesn't render.

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[Copilot]

Pull request overview

This PR refactors the new-styling authorization UX by consolidating multiple route groups into a single /authorize route and switching view selection to be driven primarily by store state (and URL search params for OpenID init/resume), including a unified redirect animation and a promise-based authorization handoff.

Changes:

• Consolidates route-based authorize flow into a single /authorize page/layout with store-driven rendering.
• Adds OpenID init/resume handling via URL search params and inlined onMount logic.
• Introduces a unified redirect animation view and updates authorization to accept Promise<bigint | undefined>.

Reviewed changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/frontend/src/routes/(new-styling)/callback/+page.svelte	Redirect OpenID callback handling to /authorize with flow=openid-resume.
src/frontend/src/routes/(new-styling)/authorize/+page.ts	Adds load-time flow detection for normal/OpenID init/OpenID resume.
src/frontend/src/routes/(new-styling)/authorize/+layout.svelte	New unified authorize layout handling channel establishment, errors, and shared chrome.
src/frontend/src/routes/(new-styling)/authorize/+page.svelte	New single authorize page selecting views by store state and flow.
src/frontend/src/routes/(new-styling)/authorize/views/AuthWizardView.svelte	Extracts auth wizard view and switches to prop-driven handlers.
src/frontend/src/routes/(new-styling)/authorize/views/ContinueView.svelte	Refactors continue/account-selection view to use props and promise-based authorization.
src/frontend/src/routes/(new-styling)/authorize/views/UpgradeSuccessView.svelte	Refactors upgrade-success view to call an injected onAuthorize handler.
src/frontend/src/routes/(new-styling)/authorize/views/RedirectAnimationView.svelte	Adds new shared redirect animation view with 10s fallback dialog.
src/frontend/src/lib/utils/reroute.ts	Removes reroute special-casing for ?openid=... since /authorize now handles it.
src/frontend/src/lib/stores/channelHandlers/delegation.ts	Awaits promised account number concurrently with authentication before delegating.
src/frontend/src/lib/stores/authorization.store.ts	Changes authorized payload to hold a promise-based account number.
src/frontend/src/routes/(new-styling)/(resuming-channel)/resume-openid-authorize/+page.svelte	Removes obsolete OpenID resume route page.
src/frontend/src/routes/(new-styling)/(resuming-channel)/+layout.svelte	Removes obsolete resuming-channel layout.
src/frontend/src/routes/(new-styling)/(pending-channel)/init-openid-authorize/+page.ts	Removes obsolete OpenID init load route.
src/frontend/src/routes/(new-styling)/(pending-channel)/init-openid-authorize/+page.svelte	Removes obsolete OpenID init redirect page.
src/frontend/src/routes/(new-styling)/(pending-channel)/+layout.svelte	Removes obsolete pending-channel layout.
src/frontend/src/routes/(new-styling)/(channel)/authorize/upgrade-success/+layout.ts	Removes obsolete route guard for upgrade-success child route.
src/frontend/src/routes/(new-styling)/(channel)/authorize/+layout.svelte	Removes obsolete channel/authorize layout (including old redirect screen).
src/frontend/src/routes/(new-styling)/(channel)/authorize/(panel)/+page.ts	Removes obsolete first-visit redirect logic to /authorize/continue.
src/frontend/src/routes/(new-styling)/(channel)/authorize/(panel)/+layout.svelte	Removes obsolete panel layout wrapper for authorize flow.
src/frontend/src/routes/(new-styling)/(channel)/+layout.svelte	Removes obsolete channel layout now replaced by unified /authorize layout.

Comments suppressed due to low confidence (1)

src/frontend/src/routes/(new-styling)/authorize/views/ContinueView.svelte:109

• accountNumberPromise can reject (e.g., get_default_account/throwCanisterError), but it's passed to onAuthorize without being awaited/handled. That means the UI commits to the authorized/redirect-animation state even if account resolution fails, and the error won't be surfaced by this try/catch. Consider resolving the account number before calling onAuthorize, or ensure the promise passed to onAuthorize never rejects (e.g., handle errors before authorizing and avoid setting authorized state on failure).

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[aterga]

Pre-approving, although the CI is red

My biggest wish for this PR is a document the code a bit better to aid navigating