(NII-Proposal) feat(files): add dynamic file provider registry for foreign addon support

[chiku-samugari]

• Ticket: []
• Feature flag: n/a

Purpose

The Files route /{guid}/files/{provider} is guarded by isFileProvider, which admits only the provider
names listed in the build-time constant FileProvider. A storage service that GravyValet serves under any
other name cannot be opened: the route does not match, the router falls through to the file-detail route,
and the page shows an empty file view for a file that does not exist.

GravyValet PR #318 (Foreign Addon Imps)
lets a deployment add storage add-on implementations as external packages. Such a service is registered in
GravyValet, served by osf.io and WaterButler, and listed on the Add-ons page, but the Files page refuses
its name. This PR removes that last build-time allow-list.

Summary of Changes

• Add FileProviderRegistryService, the registry of valid provider names.
  • The built-in FileProvider values and the external_service_name of every service returned by
    GravyValet's GET /v1/external-storage-services are registered as valid provider names.
  • Initialize the registry in initializeApplication(), which Angular runs during bootstrap and waits
    for, so that the registry is filled before the router evaluates canMatch.
  • Because the request runs during bootstrap on every page, it bypasses the global error interceptor
    (no toast, no redirect when GravyValet is unavailable), asks only for external_service_name, and
    gives up after 5 seconds.
  • If the request fails, the registry falls back to the built-in names.
  • Names are compared case-insensitively.
• Make isFileProvider ask the registry instead of the build-time list.
• Introduce a new type FileProviderType for the provider field of the files state (FilesStateModel).
  The type states what the field holds with this PR: a built-in name, or a name that GravyValet lists.
• Fall back to the name served by GravyValet for a service that the AddonServiceNames enum does not list.
  This avoids an empty name in the success toasts and in the header of the disconnect dialog.
• Tests: new spec for the registry, rewritten spec for the guard, and the initializer spec now provides the
  registry and covers the ordering (config first, bootstrap completes after the registry). New spec for
  AddonDialogService. The specs of ConnectConfiguredAddonComponent and ConnectAddonComponent were
  skipped (describe.skip); they run now, with a router mock that supplies the navigation state both
  components read in their constructor.

For deployments without foreign storage add-ons, the only change is the bootstrap request described under
Side Effects: the built-in names are always valid and every other provider-specific behaviour
(osfstorage revisions, Google Drive picker) is untouched.

Screenshot(s)

(preparing)

Side Effects

• initializeApplication() now performs network access. Until now the application initializer only
  read the local config.json. With this change it also sends one request to GravyValet
  (GET /v1/external-storage-services) on every application start, in the browser and in SSR. This is the
  first bootstrap-time dependency on a backend service, so it is relevant for QA environments, E2E test
  setups and monitoring: GravyValet is contacted before any page is rendered, including pages that have
  nothing to do with files.
  Under SSR the application starts once per rendered request, so each server-rendered page sends this
  request and waits for it, for 5 seconds at most.
• Bootstrap now waits for that request, for 5 seconds at most. A failed request is reported to Sentry by
  the interceptor's bypass path; a timeout request is not reported. Neither is visible to the user.
• The provider of the files state can now be a name that FileProvider does not list. The type
  allowed this before (it resolved to string), so this is a change of the values at run time, not of the
  types. Code that compares the provider with a built-in name must expect other values. The existing
  comparisons are equality checks with FileProvider.OsfStorage or FileProvider.GoogleDrive; a dynamic
  name takes the "is not that provider" branch, which is the intended behaviour (no revisions, no Google
  picker).

QA Notes

• Pages: Files page of a project and of a registration; project overview files widget; move/copy dialog.
• Cases:
  • a built-in provider (/{guid}/files/osfstorage, /{guid}/files/googledrive) opens as before;
  • with a foreign storage add-on configured on the project, /{guid}/files/<name> opens, including on a
    direct page load and reload;
  • an unknown name (/{guid}/files/nope) is still rejected;
  • logged-out visitor on a public project: Files page works;
  • GravyValet unreachable: the application boots.
• Add-on names (project Add-ons page and user settings Add-ons page):
  • foreign service: the disconnect dialog header and the success toast after connecting show the
    service's name instead of an empty one;
  • built-in service (e.g. Dropbox): the texts are not changed.
• Bootstrap and GravyValet availability (because the initializer now performs network access):
  • GravyValet answering slowly: the application starts after 5 seconds at the latest;
  • GravyValet answering with an error (401, 403, 5xx): no toast, no redirect to sign-in or to the
    forbidden page, the application starts with the built-in providers;
  • test environments that stub or block backend requests need an answer (or a block) for
    GET {addonsApiUrl}/external-storage-services.
• Risk: low. The guard only becomes more permissive, and only for names GravyValet lists.
• Cross-browser testing: not required.
• Requires a GravyValet that includes PR #318, with at least one foreign storage add-on registered.