feat(pr): add GitLab support

src/pr.ts

@@ -1,4 +1,4 @@
-export type Platform = "github" | "gitea";
+export type Platform = "github" | "gitea" | "gitlab";
 
 export async function getDefaultBranch(): Promise<string> {
   try {
@@ -93,16 +93,23 @@ function parseRemoteHostname(url: string): string | null {
   return hostname || null;
 }
 
+export function detectPlatformFromHostname(hostname: string | null): Platform | null {
+  if (!hostname) return null;
+
+  if (hostname === "github.com") return "github";
+  if (hostname === "gitlab.com" || hostname.includes("gitlab")) {
+    return "gitlab";
+  }
+  if (hostname.includes("gitea")) return "gitea";
+  return null;
+}
+
 export async function detectPlatform(): Promise<Platform | null> {
   try {
     const url = await Bun.$`git remote get-url origin`.quiet().text();
     const hostname = parseRemoteHostname(url);
 
-    if (!hostname) return null;
-
-    if (hostname === "github.com") return "github";
-    if (hostname.includes("gitea")) return "gitea";
-    return null;
+    return detectPlatformFromHostname(hostname);
   } catch {
     return null;
   }
@@ -118,12 +125,16 @@ export async function getRemoteHostname(): Promise<string | null> {
 }
 
 export function checkCLI(platform: Platform): string | null {
-  const bin = platform === "github" ? "gh" : "tea";
+  const bin =
+    platform === "github" ? "gh" : platform === "gitlab" ? "glab" : "tea";
   const path = Bun.which(bin);
   if (!path) {
     if (platform === "github") {
       return "GitHub CLI (gh) not found. Install: brew install gh";
     }
+    if (platform === "gitlab") {
+      return "GitLab CLI (glab) not found. Install: brew install glab";
+    }
     return "Gitea CLI (tea) not found. Install from: https://gitea.com/gitea/tea";
   }
   return null;
@@ -139,6 +150,15 @@ export async function checkAuth(platform: Platform): Promise<string | null> {
     }
   }
 
+  if (platform === "gitlab") {
+    try {
+      await Bun.$`glab auth status`.quiet();
+      return null;
+    } catch {
+      return "Not authenticated with GitLab CLI. Run: glab auth login";
+    }
+  }
+
   try {
     const result = await Bun.$`tea logins list`.quiet().text();
     if (result.trim()) return null;
@@ -186,6 +206,37 @@ export async function createPR(
     return match?.[1] ?? stdout.trim();
   }
 
+  if (platform === "gitlab") {
+    const args = [
+      "mr",
+      "create",
+      "--title",
+      title,
+      "--description",
+      body,
+      "--target-branch",
+      base,
+    ];
+    if (draft) args.push("--draft");
+
+    const proc = Bun.spawn(["glab", ...args], {
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    const exitCode = await proc.exited;
+    const stdout = await new Response(proc.stdout).text();
+    const stderr = await new Response(proc.stderr).text();
+
+    if (exitCode !== 0) {
+      throw new Error(
+        stderr.trim() || `glab mr create failed (exit code ${exitCode})`,
+      );
+    }
+
+    const match = stdout.match(/(https?:\/\/[^\s]+)/);
+    return match?.[1] ?? stdout.trim();
+  }
+
   const args = [
     "pulls",
     "create",