feat: Implement Cursor CLI Provider and Configuration Manager

- Added CursorConfigManager to manage Cursor CLI configuration, including loading, saving, and resetting settings.
- Introduced CursorProvider to integrate the cursor-agent CLI, handling installation checks, authentication, and query execution.
- Enhanced error handling with detailed CursorError codes for better debugging and user feedback.
- Updated documentation to reflect the completion of the Cursor Provider implementation phase.

plan/cursor-cli-integration/phases/phase-2-provider.md

@@ -1,6 +1,6 @@
 # Phase 2: Cursor Provider Implementation
 
-**Status:** `pending`
+**Status:** `completed`
 **Dependencies:** Phase 1 (Types)
 **Estimated Effort:** Medium-Large (core implementation)
 
@@ -16,7 +16,7 @@ Implement the main `CursorProvider` class that spawns the cursor-agent CLI and s
 
 ### Task 2.1: Create Cursor Provider
 
-**Status:** `pending`
+**Status:** `completed`
 
 **File:** `apps/server/src/providers/cursor-provider.ts`
 
@@ -635,7 +635,7 @@ export class CursorProvider extends BaseProvider {
 
 ### Task 2.2: Create Cursor Config Manager
 
-**Status:** `pending`
+**Status:** `completed`
 
 **File:** `apps/server/src/providers/cursor-config-manager.ts`