feat(team-member): Complete Team Member Management capability

Implement full CRUD operations for team members with TDD approach:

Backend:
- TeamMemberController with REST API endpoints
- TeamMemberService for business logic extraction
- TeamMemberPolicy for authorization (superuser/manager access)
- 14 tests passing (8 API, 6 unit tests)

Frontend:
- Team member list with search and status filter
- Create/Edit modal with form validation
- Delete confirmation with constraint checking
- Currency formatting for hourly rates
- Real API integration with teamMemberService

Tests:
- E2E tests fixed with seed data helper
- All 157 tests passing (backend + frontend + E2E)

Closes #22

backend/tests/Unit/Models/TeamMemberModelTest.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Tests\Unit\Models;
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+use App\Models\TeamMember;
+use App\Models\Role;
+
+class TeamMemberModelTest extends TestCase
+{
+    use RefreshDatabase;
+
+    // 2.1.17 Unit test: TeamMember model validation
+    public function test_team_member_model_validation()
+    {
+        $role = Role::factory()->create();
+
+        // Test valid team member
+        $teamMember = TeamMember::factory()->create([
+            'role_id' => $role->id,
+            'name' => 'John Doe',
+            'hourly_rate' => 150.00,
+            'active' => true,
+        ]);
+
+        $this->assertInstanceOf(TeamMember::class, $teamMember);
+        $this->assertEquals('John Doe', $teamMember->name);
+        $this->assertEquals('150.00', $teamMember->hourly_rate);
+        $this->assertTrue($teamMember->active);
+        $this->assertEquals($role->id, $teamMember->role_id);
+
+        // Test casts
+        $this->assertIsBool($teamMember->active);
+        $this->assertIsString($teamMember->hourly_rate);
+    }
+
+    public function test_team_member_has_role_relationship()
+    {
+        $role = Role::factory()->create(['name' => 'Backend Developer']);
+        $teamMember = TeamMember::factory()->create(['role_id' => $role->id]);
+
+        $this->assertInstanceOf(Role::class, $teamMember->role);
+        $this->assertEquals('Backend Developer', $teamMember->role->name);
+    }
+}