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/types.ts

@@ -0,0 +1,56 @@
+import type { ParsedGitHubContext } from "../github/context";
+import type { ModeName } from "./registry";
+
+export type ModeContext = {
+  mode: ModeName;
+  githubContext: ParsedGitHubContext;
+  commentId?: number;
+  baseBranch?: string;
+  claudeBranch?: string;
+};
+
+export type ModeData = {
+  commentId?: number;
+  baseBranch?: string;
+  claudeBranch?: string;
+};
+
+/**
+ * Mode interface for claude-code-action execution modes.
+ * Each mode defines its own behavior for trigger detection, prompt generation,
+ * and tracking comment creation.
+ *
+ * Future modes might include:
+ * - 'review': Optimized for code reviews without tracking comments
+ * - 'freeform': For automation with no trigger checking
+ */
+export type Mode = {
+  name: ModeName;
+  description: string;
+
+  /**
+   * Determines if this mode should trigger based on the GitHub context
+   */
+  shouldTrigger(context: ParsedGitHubContext): boolean;
+
+  /**
+   * Prepares the mode context with any additional data needed for prompt generation
+   */
+  prepareContext(context: ParsedGitHubContext, data?: ModeData): ModeContext;
+
+  /**
+   * Returns additional tools that should be allowed for this mode
+   * (base GitHub tools are always included)
+   */
+  getAllowedTools(): string[];
+
+  /**
+   * Returns tools that should be disallowed for this mode
+   */
+  getDisallowedTools(): string[];
+
+  /**
+   * Determines if this mode should create a tracking comment
+   */
+  shouldCreateTrackingComment(): boolean;
+};