Add just check command.

CLAUDE.md

@@ -74,38 +74,11 @@ tasks (id, title, description, status, created_at, updated_at, completed_at)
 
 ## Development Commands
 
-### Testing
-```bash
-# Backend tests
-just test-unit              # Unit tests (cargo test)
-just test-coverage          # Coverage report (tarpaulin HTML)
-just test-integration       # API tests (Hurl)
+**Primary command**: Use `just` for all development tasks. Run `just --list` to see all available commands.
 
-# Individual commands
-cargo test                  # Direct unit test execution
-hurl --test tests/api/*.hurl # Direct API test execution
-
-# Frontend tests (when implemented)
-npm test                    # Unit tests
-npm run test:e2e           # End-to-end tests
-npm run test:coverage      # Coverage report
-```
-
-### Development Server
-```bash
-# Backend (Rust server)
-just dev                    # Run backend server (cargo run)
-
-# Other backend commands
-just build                  # Build project
-just migrate               # Run database migrations
-just reset-db              # Reset database
-just fmt                   # Format code
-just lint                  # Run clippy
-
-# Frontend (when implemented)
-npm run dev                # Vite dev server
-```
+**Key commands**:
+- `just check` - Validate all changes (primary validation command)
+- `just fmt` - Format code (resolve formatting errors)
 
 ## Current Phase: Core MVP Backend ✅