Add PDF reports, file uploads, admin auth, and comprehensive tests

Features:
- PDF service for generating task reports with ReportLab-style formatting
- Storage service for file uploads (local and S3-compatible)
- Admin authentication middleware with JWT support
- Admin user model and repository

Infrastructure:
- Updated Docker configuration for admin panel builds
- Email service enhancements for task notifications
- Updated router with admin and file upload routes
- Environment configuration updates

Tests:
- Unit tests for handlers (auth, residence, task)
- Unit tests for models (user, residence, task)
- Unit tests for repositories (user, residence, task)
- Unit tests for services (residence, task)
- Integration test setup
- Test utilities for mocking database and services

Database:
- Admin user seed data
- Updated test data seeds

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/models/admin.go

@@ -0,0 +1,63 @@
+package models
+
+import (
+	"time"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// AdminRole represents the role of an admin user
+type AdminRole string
+
+const (
+	AdminRoleAdmin      AdminRole = "admin"
+	AdminRoleSuperAdmin AdminRole = "super_admin"
+)
+
+// AdminUser represents an administrator for the admin panel
+type AdminUser struct {
+	ID        uint       `gorm:"primaryKey" json:"id"`
+	Email     string     `gorm:"uniqueIndex;size:254;not null" json:"email"`
+	Password  string     `gorm:"size:128;not null" json:"-"`
+	FirstName string     `gorm:"size:100" json:"first_name"`
+	LastName  string     `gorm:"size:100" json:"last_name"`
+	Role      AdminRole  `gorm:"size:20;default:'admin'" json:"role"`
+	IsActive  bool       `gorm:"default:true" json:"is_active"`
+	LastLogin *time.Time `json:"last_login,omitempty"`
+	CreatedAt time.Time  `json:"created_at"`
+	UpdatedAt time.Time  `json:"updated_at"`
+}
+
+// TableName specifies the table name for AdminUser
+func (AdminUser) TableName() string {
+	return "admin_users"
+}
+
+// SetPassword hashes and sets the password
+func (a *AdminUser) SetPassword(password string) error {
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return err
+	}
+	a.Password = string(hash)
+	return nil
+}
+
+// CheckPassword verifies the password against the stored hash
+func (a *AdminUser) CheckPassword(password string) bool {
+	err := bcrypt.CompareHashAndPassword([]byte(a.Password), []byte(password))
+	return err == nil
+}
+
+// FullName returns the admin's full name
+func (a *AdminUser) FullName() string {
+	if a.FirstName == "" && a.LastName == "" {
+		return a.Email
+	}
+	return a.FirstName + " " + a.LastName
+}
+
+// IsSuperAdmin checks if the admin has super admin privileges
+func (a *AdminUser) IsSuperAdmin() bool {
+	return a.Role == AdminRoleSuperAdmin
+}