feat(web,ui): per-project forced git provider and settings gating

Adds a per-project forced provider (github|gitlab|gitea) on top of the
per-project API base URL overrides: stored under gitProviders.provider in
projects/<projectId>.json, sanitized server-side, and winning over remote-host
detection both in useGitProvider and in server repo resolution
(parseGitLabRemoteUrl/parseGiteaRemoteUrl accept any host when the provider
is forced). The Projects settings page replaces the three always-visible URL
fields with a provider selector (auto-detect + the three forges) and one URL
override for the active provider. Global provider override fields on the
GitHub/GitLab/Gitea settings tabs now render only once an account is
connected, and Settings search availability matches that gating.

Also fixes the useConfigStore/useDirectoryStore circular-import TDZ in the
bundled chunk via the window-registered store handle and defers the directory
subscription to a microtask; fixes the Gitea PR merge payload (Do carries the
merge-style string enum, not a boolean + MergeMethod); and adds a documented
Gitea client live-test harness (scripts/gitea-live-test.ts + client.d.ts).

packages/web/server/lib/gitlab/repo.test.js

@@ -22,6 +22,12 @@ vi.mock('../git-providers/project-config.js', async (importOriginal) => {
       }
       return actual.getEffectiveProviderApiBaseUrl(provider, directory);
     }),
+    getProjectProviderFromDirectory: vi.fn((directory) => {
+      if (directory === '/forced/project') {
+        return 'gitlab';
+      }
+      return actual.getProjectProviderFromDirectory(directory);
+    }),
   };
 });
 
@@ -147,4 +153,11 @@ describe('resolveGitLabRepoFromDirectory', () => {
     const { repo } = await resolveGitLabRepoFromDirectory('/some/project');
     expect(repo).toBeNull();
   });
+
+  test('accepts any remote host when the provider is forced to gitlab', async () => {
+    vi.mocked(getRemoteUrl).mockResolvedValue('git@gitlab.internal.corp:team/app.git');
+    const { repo, remoteUrl } = await resolveGitLabRepoFromDirectory('/forced/project');
+    expect(remoteUrl).toBe('git@gitlab.internal.corp:team/app.git');
+    expect(repo).toMatchObject({ namespace: 'team', project: 'app', host: 'gitlab.internal.corp' });
+  });
 });