fix(prd-1): handle undefined actor type on Forgejo

Forgejo's user API doesn't return a `type` field (GitHub returns
"User" or "Bot"). The undefined type was incorrectly treated as
non-human, blocking all Forgejo workflows. Now treat undefined/empty
type as human — Forgejo doesn't have GitHub-style bot accounts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

test/actor.test.ts

@@ -93,4 +93,21 @@ describe("checkHumanActor", () => {
       "Workflow initiated by non-human actor: other-bot (type: Bot). Add bot to allowed_bots list or use '*' to allow all bots.",
     );
   });
+
+  test("should treat undefined actor type as human (Forgejo compatibility)", async () => {
+    // Forgejo's user API doesn't return a `type` field
+    const mockOctokit = {
+      users: {
+        getByUsername: async () => ({
+          data: {},
+        }),
+      },
+    } as unknown as Octokit;
+    const context = createMockContext();
+    context.actor = "forgejo-user";
+
+    await expect(
+      checkHumanActor(mockOctokit, context),
+    ).resolves.toBeUndefined();
+  });
 });