Add mode support (#333)

* Add mode support

* update "as any" with proper "as unknwon as ModeName" casting

* Add documentation to README and registry.ts

* Add  tests for differen event types, integration flows, and error conditions

* Clean up some tests

* Minor test fix

* Minor formatting test + switch from interface to type

* correct the order of mkdir call

* always configureGitAuth as there's already a fallback to handle null users by using the bot ID

* simplify registry setup

---------

Co-authored-by: km-anthropic <km-anthropic@users.noreply.github.com>

src/modes/tag/index.ts

@@ -0,0 +1,40 @@
+import type { Mode } from "../types";
+import { checkContainsTrigger } from "../../github/validation/trigger";
+
+/**
+ * Tag mode implementation.
+ *
+ * The traditional implementation mode that responds to @claude mentions,
+ * issue assignments, or labels. Creates tracking comments showing progress
+ * and has full implementation capabilities.
+ */
+export const tagMode: Mode = {
+  name: "tag",
+  description: "Traditional implementation mode triggered by @claude mentions",
+
+  shouldTrigger(context) {
+    return checkContainsTrigger(context);
+  },
+
+  prepareContext(context, data) {
+    return {
+      mode: "tag",
+      githubContext: context,
+      commentId: data?.commentId,
+      baseBranch: data?.baseBranch,
+      claudeBranch: data?.claudeBranch,
+    };
+  },
+
+  getAllowedTools() {
+    return [];
+  },
+
+  getDisallowedTools() {
+    return [];
+  },
+
+  shouldCreateTrackingComment() {
+    return true;
+  },
+};