feat: add allow_bot_users option to control bot user access

- Add allow_bot_users input parameter (default: false)
- Modify checkHumanActor to optionally allow bot users
- Add comprehensive tests for bot user handling
- Improve security by blocking bot users by default

This change prevents potential prompt injection attacks from bot users
while providing flexibility for trusted bot integrations.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

test/actor.test.ts

@@ -0,0 +1,72 @@
+#!/usr/bin/env bun
+
+import { describe, test, expect } from "bun:test";
+import { checkHumanActor } from "../src/github/validation/actor";
+import type { Octokit } from "@octokit/rest";
+import { createMockContext } from "./mockContext";
+
+function createMockOctokit(userType: string): Octokit {
+  return {
+    users: {
+      getByUsername: async () => ({
+        data: {
+          type: userType,
+        },
+      }),
+    },
+  } as unknown as Octokit;
+}
+
+describe("checkHumanActor", () => {
+  test("should pass for human actor", async () => {
+    const mockOctokit = createMockOctokit("User");
+    const context = createMockContext();
+    context.actor = "human-user";
+
+    await expect(
+      checkHumanActor(mockOctokit, context, ""),
+    ).resolves.toBeUndefined();
+  });
+
+  test("should throw error for bot actor when not allowed", async () => {
+    const mockOctokit = createMockOctokit("Bot");
+    const context = createMockContext();
+    context.actor = "test-bot";
+
+    await expect(checkHumanActor(mockOctokit, context, "")).rejects.toThrow(
+      "Workflow initiated by non-human actor: test-bot (type: Bot). Add bot to allowed_bots list or use '*' to allow all bots.",
+    );
+  });
+
+  test("should pass for bot actor when all bots allowed", async () => {
+    const mockOctokit = createMockOctokit("Bot");
+    const context = createMockContext();
+    context.actor = "test-bot";
+
+    await expect(
+      checkHumanActor(mockOctokit, context, "*"),
+    ).resolves.toBeUndefined();
+  });
+
+  test("should pass for specific bot when in allowed list", async () => {
+    const mockOctokit = createMockOctokit("Bot");
+    const context = createMockContext();
+    context.actor = "dependabot";
+
+    await expect(
+      checkHumanActor(mockOctokit, context, "dependabot,renovate"),
+    ).resolves.toBeUndefined();
+  });
+
+  test("should throw error for bot not in allowed list", async () => {
+    const mockOctokit = createMockOctokit("Bot");
+    const context = createMockContext();
+    context.actor = "other-bot";
+
+    await expect(
+      checkHumanActor(mockOctokit, context, "dependabot,renovate"),
+    ).rejects.toThrow(
+      "Workflow initiated by non-human actor: other-bot (type: Bot). Add bot to allowed_bots list or use '*' to allow all bots.",
+    );
+  });
+});