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/app/Services/TeamMemberService.php

@@ -0,0 +1,160 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\TeamMember;
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Validation\ValidationException;
+use Illuminate\Support\Facades\Validator;
+
+/**
+ * Team Member Service
+ *
+ * Handles business logic for team member operations.
+ */
+class TeamMemberService
+{
+    /**
+     * Get all team members with optional filtering.
+     *
+     * @param bool|null $active Filter by active status
+     * @return Collection<TeamMember>
+     */
+    public function getAll(?bool $active = null): Collection
+    {
+        $query = TeamMember::with('role');
+
+        if ($active !== null) {
+            $query->where('active', $active);
+        }
+
+        return $query->get();
+    }
+
+    /**
+     * Find a team member by ID.
+     *
+     * @param string $id
+     * @return TeamMember|null
+     */
+    public function findById(string $id): ?TeamMember
+    {
+        return TeamMember::with('role')->find($id);
+    }
+
+    /**
+     * Create a new team member.
+     *
+     * @param array $data
+     * @return TeamMember
+     * @throws ValidationException
+     */
+    public function create(array $data): TeamMember
+    {
+        $validator = Validator::make($data, [
+            'name' => 'required|string|max:255',
+            'role_id' => 'required|integer|exists:roles,id',
+            'hourly_rate' => 'required|numeric|gt:0',
+            'active' => 'boolean',
+        ], [
+            'hourly_rate.gt' => 'Hourly rate must be greater than 0',
+        ]);
+
+        if ($validator->fails()) {
+            throw new ValidationException($validator);
+        }
+
+        $teamMember = TeamMember::create([
+            'name' => $data['name'],
+            'role_id' => $data['role_id'],
+            'hourly_rate' => $data['hourly_rate'],
+            'active' => $data['active'] ?? true,
+        ]);
+
+        $teamMember->load('role');
+
+        return $teamMember;
+    }
+
+    /**
+     * Update an existing team member.
+     *
+     * @param TeamMember $teamMember
+     * @param array $data
+     * @return TeamMember
+     * @throws ValidationException
+     */
+    public function update(TeamMember $teamMember, array $data): TeamMember
+    {
+        $validator = Validator::make($data, [
+            'name' => 'sometimes|string|max:255',
+            'role_id' => 'sometimes|integer|exists:roles,id',
+            'hourly_rate' => 'sometimes|numeric|gt:0',
+            'active' => 'sometimes|boolean',
+        ], [
+            'hourly_rate.gt' => 'Hourly rate must be greater than 0',
+        ]);
+
+        if ($validator->fails()) {
+            throw new ValidationException($validator);
+        }
+
+        $teamMember->update($data);
+        $teamMember->load('role');
+
+        return $teamMember;
+    }
+
+    /**
+     * Delete a team member.
+     *
+     * @param TeamMember $teamMember
+     * @return void
+     * @throws \RuntimeException
+     */
+    public function delete(TeamMember $teamMember): void
+    {
+        // Check if team member has allocations
+        if ($teamMember->allocations()->exists()) {
+            throw new \RuntimeException(
+                'Cannot delete team member with active allocations',
+                422
+            );
+        }
+
+        // Check if team member has actuals
+        if ($teamMember->actuals()->exists()) {
+            throw new \RuntimeException(
+                'Cannot delete team member with historical data',
+                422
+            );
+        }
+
+        $teamMember->delete();
+    }
+
+    /**
+     * Check if a team member can be deleted.
+     *
+     * @param TeamMember $teamMember
+     * @return array{canDelete: bool, reason?: string}
+     */
+    public function canDelete(TeamMember $teamMember): array
+    {
+        if ($teamMember->allocations()->exists()) {
+            return [
+                'canDelete' => false,
+                'reason' => 'Team member has active allocations',
+            ];
+        }
+
+        if ($teamMember->actuals()->exists()) {
+            return [
+                'canDelete' => false,
+                'reason' => 'Team member has historical data',
+            ];
+        }
+
+        return ['canDelete' => true];
+    }
+}