feat: add entity exposure detection (v0.3.0)

Implement entity exposure detection to prevent domain entities
from leaking to API responses. Detects when controllers/routes
return domain entities instead of DTOs.

Features:
- EntityExposure value object with detailed suggestions
- IEntityExposureDetector interface in domain layer
- EntityExposureDetector implementation in infrastructure
- Integration into AnalyzeProject use case
- CLI display with helpful suggestions
- 24 comprehensive unit tests (98% coverage)
- Examples for bad and good patterns

Detection scope:
- Infrastructure layer only (controllers, routes, handlers, resolvers, gateways)
- Identifies PascalCase entities without Dto/Request/Response suffixes
- Parses async methods with Promise<T> return types
- Provides step-by-step remediation suggestions

Test coverage:
- EntityExposureDetector: 98.07%
- Overall project: 90.6% statements, 83.97% branches
- 218 tests passing

BREAKING CHANGE: Version bump to 0.3.0

packages/guardian/examples/good-architecture/entity-exposure/GoodUserController.ts

@@ -0,0 +1,42 @@
+// ✅ GOOD: Using DTOs and Mappers instead of exposing domain entities
+
+class User {
+    constructor(
+        private readonly id: string,
+        private email: string,
+        private password: string,
+    ) {}
+
+    getId(): string {
+        return this.id
+    }
+
+    getEmail(): string {
+        return this.email
+    }
+}
+
+class UserResponseDto {
+    constructor(
+        public readonly id: string,
+        public readonly email: string,
+    ) {}
+}
+
+class UserMapper {
+    static toDto(user: User): UserResponseDto {
+        return new UserResponseDto(user.getId(), user.getEmail())
+    }
+}
+
+class GoodUserController {
+    async getUser(userId: string): Promise<UserResponseDto> {
+        const user = new User(userId, "user@example.com", "hashed-password")
+        return UserMapper.toDto(user)
+    }
+
+    async listUsers(): Promise<UserResponseDto[]> {
+        const users = [new User("1", "user1@example.com", "password")]
+        return users.map((user) => UserMapper.toDto(user))
+    }
+}