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/git-providers/project-config.test.js

@@ -12,6 +12,8 @@ process.env.OPENCHAMBER_DATA_DIR = TEMP_DATA_DIR;
 const {
   sanitizeProjectGitProviders,
   getProjectGitProviders,
+  getProjectProvider,
+  getProjectProviderFromDirectory,
   resolveProjectIdFromDirectory,
   getProjectProviderApiBaseUrl,
   getEffectiveProviderApiBaseUrl,
@@ -73,6 +75,46 @@ describe('sanitizeProjectGitProviders', () => {
     expect(sanitizeProjectGitProviders([])).toBeUndefined();
     expect(getProjectGitProviders('proj_1')).toEqual({});
   });
+
+  test('keeps a forced provider when it is one of the known providers', () => {
+    expect(sanitizeProjectGitProviders({
+      provider: 'GitLab',
+      gitlab: { apiBaseUrl: 'gitlab.example.com' },
+    })).toEqual({
+      provider: 'gitlab',
+      gitlab: { apiBaseUrl: 'https://gitlab.example.com' },
+    });
+  });
+
+  test('drops an unknown or empty forced provider', () => {
+    expect(sanitizeProjectGitProviders({
+      provider: 'bitbucket',
+      github: { apiBaseUrl: 'github.example.com' },
+    })).toEqual({ github: { apiBaseUrl: 'https://github.example.com' } });
+    expect(sanitizeProjectGitProviders({ provider: '' })).toBeUndefined();
+    expect(sanitizeProjectGitProviders({ provider: '  ' })).toBeUndefined();
+  });
+});
+
+describe('getProjectProvider / getProjectProviderFromDirectory', () => {
+  test('returns the forced provider or null', () => {
+    fs.mkdirSync(PROJECTS_DIR, { recursive: true });
+    fs.writeFileSync(projectFile('proj_provider'), JSON.stringify({
+      gitProviders: { provider: 'gitea', gitea: { apiBaseUrl: 'https://gitea.example.com' } },
+    }, null, 2));
+    expect(getProjectProvider('proj_provider')).toBe('gitea');
+    expect(getProjectProvider('proj_missing')).toBeNull();
+  });
+
+  test('resolves the forced provider through the directory', () => {
+    fs.mkdirSync(PROJECTS_DIR, { recursive: true });
+    fs.writeFileSync(projectFile('proj_forced'), JSON.stringify({
+      gitProviders: { provider: 'gitlab' },
+    }, null, 2));
+    writeSettingsProjects([{ id: 'proj_forced', path: '/home/user/gl' }]);
+    expect(getProjectProviderFromDirectory('/home/user/gl')).toBe('gitlab');
+    expect(getProjectProviderFromDirectory('/home/user/unregistered')).toBeNull();
+  });
 });
 
 describe('saveProjectGitProviders round-trip', () => {