fix(vscode-ide-companion): resolve ESLint errors and improve code quality

- Fix unused variable issues by removing unused variables and renaming caught errors to match ESLint rules
- Fix TypeScript type mismatches in mode handling
- Add missing curly braces to if statements to comply with ESLint rules
- Resolve missing dependency warnings in React hooks
- Clean up empty catch blocks by adding appropriate comments
- Remove unused _lastEditorState variables that were declared but never read

These changes ensure the codebase passes ESLint checks and follows best practices for code quality.

packages/vscode-ide-companion/src/constants/acpSchema.ts

@@ -13,6 +13,7 @@ export const AGENT_METHODS = {
   session_new: 'session/new',
   session_prompt: 'session/prompt',
   session_save: 'session/save',
+  session_set_mode: 'session/set_mode',
 } as const;
 
 export const CLIENT_METHODS = {

packages/vscode-ide-companion/src/constants/acpTypes.ts

@@ -153,6 +153,17 @@ export interface PlanUpdate extends BaseSessionUpdate {
   };
 }
 
+// Approval/Mode values as defined by ACP schema
+export type ApprovalModeValue = 'plan' | 'default' | 'auto-edit' | 'yolo';
+
+// Current mode update (sent by agent when mode changes)
+export interface CurrentModeUpdate extends BaseSessionUpdate {
+  update: {
+    sessionUpdate: 'current_mode_update';
+    modeId: ApprovalModeValue;
+  };
+}
+
 // Union type for all session updates
 export type AcpSessionUpdate =
   | UserMessageChunkUpdate
@@ -160,7 +171,8 @@ export type AcpSessionUpdate =
   | AgentThoughtChunkUpdate
   | ToolCallUpdate
   | ToolCallStatusUpdate
-  | PlanUpdate;
+  | PlanUpdate
+  | CurrentModeUpdate;
 
 // Permission request (simplified version, use schema.RequestPermissionRequest for validation)
 export interface AcpPermissionRequest {