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/ui/src/lib/settings/search.ts

@@ -28,6 +28,8 @@ interface SettingsSearchAvailabilityContext extends SettingsRuntimeContext {
   isLinux: boolean;
   // Windows ARM64 — temporary workaround gate (see opencode#19130).
   isWindowsArm64: boolean;
+  // Git provider override fields only render once an account is connected.
+  gitProvidersConnected: { github: boolean; gitlab: boolean; gitea: boolean };
 }
 
 const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
@@ -507,6 +509,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.github.page.apiBaseUrl.label',
     descriptionKey: 'settings.github.page.apiBaseUrl.description',
     keywords: ['github', 'api', 'base url', 'enterprise', 'self-hosted', 'server'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.github,
   },
   {
     id: 'git.github-detect-urls',
@@ -514,6 +517,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.github.page.detectUrls.label',
     descriptionKey: 'settings.github.page.detectUrls.description',
     keywords: ['github', 'detect', 'remote', 'host', 'domain', 'ssh', 'url', 'self-hosted'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.github,
   },
   {
     id: 'git.gitlab-api-base-url',
@@ -521,6 +525,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.gitlab.page.apiBaseUrl.label',
     descriptionKey: 'settings.gitlab.page.apiBaseUrl.description',
     keywords: ['gitlab', 'api', 'base url', 'self-hosted', 'server', 'instance'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.gitlab,
   },
   {
     id: 'git.gitlab-detect-urls',
@@ -528,6 +533,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.gitlab.page.detectUrls.label',
     descriptionKey: 'settings.gitlab.page.detectUrls.description',
     keywords: ['gitlab', 'detect', 'remote', 'host', 'domain', 'ssh', 'url', 'self-hosted'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.gitlab,
   },
   {
     id: 'git.gitea-api-base-url',
@@ -535,6 +541,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.gitea.page.apiBaseUrl.label',
     descriptionKey: 'settings.gitea.page.apiBaseUrl.description',
     keywords: ['gitea', 'forgejo', 'api', 'base url', 'self-hosted', 'server', 'instance'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.gitea,
   },
   {
     id: 'git.gitea-detect-urls',
@@ -542,6 +549,7 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     titleKey: 'settings.gitea.page.detectUrls.label',
     descriptionKey: 'settings.gitea.page.detectUrls.description',
     keywords: ['gitea', 'forgejo', 'detect', 'remote', 'host', 'domain', 'ssh', 'url', 'self-hosted'],
+    isAvailable: (ctx) => ctx.gitProvidersConnected.gitea,
   },
   {
     id: 'git.identities',
@@ -616,7 +624,14 @@ const SETTINGS_SEARCH_ITEMS: readonly SettingsSearchItem[] = [
     page: 'projects',
     titleKey: 'settings.projects.page.gitProviders.title',
     descriptionKey: 'settings.projects.page.gitProviders.description',
-    keywords: ['github', 'gitlab', 'gitea', 'api base url', 'self-hosted', 'override', 'enterprise', 'server'],
+    keywords: ['github', 'gitlab', 'gitea', 'api base url', 'self-hosted', 'override', 'enterprise', 'server', 'provider', 'forge'],
+  },
+  {
+    id: 'projects.git-providers.provider',
+    page: 'projects',
+    titleKey: 'settings.projects.page.gitProviders.provider.label',
+    descriptionKey: 'settings.projects.page.gitProviders.provider.description',
+    keywords: ['github', 'gitlab', 'gitea', 'provider', 'forge', 'auto-detect', 'detection'],
   },
   {
     id: 'remote-instances.client-auth',