feat(forge): pluggable forge abstraction + GitLab and Gitea/Forgejo/Codeberg (#1913)

* refactor(forge): forge-neutral foundation (GitHub-only)

Decouple git-hosting from GitHub behind a neutral abstraction (issue #1616), GitHub-only for now; existing GitHub behaviour is unchanged.

- Forge manifest, neutral ForgeService contract, forge registry + resolver, and a client forge-module registry.
- GitHub code renamed to the neutral shape; PR/Issue attachment wording preserved.
- forge.search.response enums parse tolerantly (unknown kind/auth state degrade instead of breaking the client).
- createPullRequest reports typed CLI/auth errors instead of a generic message.
- forge-resolver host/remote caches are LRU-bounded.
- Forge host trust is explicit: only a known cloud host or a CLI-authenticated host is ever talked to; an unauthenticated GitHub Enterprise host fails resolution instead of routing to github.com.
- Docs: forge-providers guide, glossary and i18n forge-copy conventions, architecture and rpc-namespacing terminology.
- Vitest React Native mocks (unistyles, svg, linking, lucide) consolidated into shared aliased test-stubs.

* feat(forge): GitLab adapter, forge-aware UI, pipelines and approvals

GitLab adapter over the glab CLI on the neutral contracts: MR status, forge-aware UI, pipeline tree, and N-of-M approvals.

- threadIsResolved is part of the neutral timeline item.
- Pipeline load failures show an error instead of an empty section.
- Manual pipeline jobs render as pending.
- Fork/detached MR head pipelines are fetched by MR iid (glab ci get --merge-request).

* feat(forge): Gitea family adapter (Gitea, Forgejo, Codeberg)

One adapter over the tea CLI serving Gitea, Forgejo, and Codeberg on the neutral contracts.

- CI status aggregates commit statuses and Actions runs together.
- Gitea's terminal "warning" state maps to failure on server and client.
- Gitea Actions check details are reachable from the PR pane by workflowRunId.

* refactor(forge): localize compatibility handling

* test(forge): expect normalized GitLab facts

---------

Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

packages/app/src/git/actions-store.ts

@@ -42,11 +42,19 @@ function resolveClient(serverId: string) {
   return client;
 }
 
-function assertGitHubAutoMergeActionsSupported(serverId: string) {
+type AutoMergeActionsRpc = "forge" | "github";
+
+function resolveAutoMergeActionsRpc(serverId: string): AutoMergeActionsRpc {
   const session = useSessionStore.getState().sessions[serverId];
-  if (session?.serverInfo?.features?.checkoutGithubSetAutoMerge !== true) {
-    throw new Error("Update the host to use GitHub auto-merge actions.");
+  if (session?.serverInfo?.features?.checkoutForgeSetAutoMerge === true) {
+    return "forge";
   }
+  // COMPAT(githubAutoMergeRpc): added in v0.1.106, remove after 2026-12-28 once
+  // all supported clients use checkout.forge.set_auto_merge.*.
+  if (session?.serverInfo?.features?.checkoutGithubSetAutoMerge === true) {
+    return "github";
+  }
+  throw new Error("Update the host to use auto-merge actions.");
 }
 
 function setStatus(
@@ -281,14 +289,19 @@ export const useCheckoutGitActionsStore = create<CheckoutGitActionsStoreState>()
   },
 
   enablePrAutoMerge: async ({ serverId, cwd, method }) => {
-    assertGitHubAutoMergeActionsSupported(serverId);
+    const rpc = resolveAutoMergeActionsRpc(serverId);
     await runCheckoutAction({
       serverId,
       cwd,
       actionId: `enable-pr-auto-merge-${method}`,
       run: async () => {
         const client = resolveClient(serverId);
-        const payload = await client.checkoutGithubSetAutoMerge(cwd, { enabled: true, method });
+        // COMPAT(githubAutoMergeRpc): added in v0.1.106, remove after 2026-12-28 once
+        // all supported clients use checkout.forge.set_auto_merge.*.
+        const payload =
+          rpc === "forge"
+            ? await client.checkoutForgeSetAutoMerge(cwd, { enabled: true, method })
+            : await client.checkoutGithubSetAutoMerge(cwd, { enabled: true, method });
         if (payload.error) {
           throw new Error(payload.error.message);
         }
@@ -297,14 +310,19 @@ export const useCheckoutGitActionsStore = create<CheckoutGitActionsStoreState>()
   },
 
   disablePrAutoMerge: async ({ serverId, cwd }) => {
-    assertGitHubAutoMergeActionsSupported(serverId);
+    const rpc = resolveAutoMergeActionsRpc(serverId);
     await runCheckoutAction({
       serverId,
       cwd,
       actionId: "disable-pr-auto-merge",
       run: async () => {
         const client = resolveClient(serverId);
-        const payload = await client.checkoutGithubSetAutoMerge(cwd, { enabled: false });
+        // COMPAT(githubAutoMergeRpc): added in v0.1.106, remove after 2026-12-28 once
+        // all supported clients use checkout.forge.set_auto_merge.*.
+        const payload =
+          rpc === "forge"
+            ? await client.checkoutForgeSetAutoMerge(cwd, { enabled: false })
+            : await client.checkoutGithubSetAutoMerge(cwd, { enabled: false });
         if (payload.error) {
           throw new Error(payload.error.message);
         }