refactor: Update type definitions for structured file editing

- Add Action, EditAction, FileDiff, and Diff types
- Replace simple diff string with structured Diff[] format
- Add action property to Message interface
- Support extensible action system for future features

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

Co-Authored-By: Claude <[email protected]>

Author: koki-develop

src/components/types.ts

@@ -1,5 +1,24 @@
-export interface Message {
+export type Action = EditAction;
+
+export type EditAction = {
+  type: "edit";
+  diff: FileDiff;
+};
+
+export type FileDiff = {
+  fileName: string;
+  diffs: Diff[];
+};
+
+export type Diff = {
+  rowNumber: number;
+  a: string;
+  b: string;
+};
+
+export type Message = {
   id: number;
   text: string;
   sender: "user" | "cat";
-}
+  action?: Action;
+};