feat(frontend): add reusable form validators

- Create emailValidator with stricter pattern than Angular's built-in
- Create nameValidator with configurable minLength, maxLength, allowNumbers
- Support for Spanish characters (accents, ñ, ü)
- Export validators from shared module
- Add JSDoc documentation with usage examples

src/frontend/src/app/shared/index.ts

@@ -7,3 +7,7 @@ export * from './components/ui/connectivity-overlay/connectivity-overlay.compone
 // Pipes
 export * from './pipes/credits.pipe';
 export * from './pipes/initials.pipe';
+
+// Validators
+export * from './validators/email.validator';
+export * from './validators/name.validator';

src/frontend/src/app/shared/validators/email.validator.ts

@@ -0,0 +1,30 @@
+import { AbstractControl, ValidationErrors, ValidatorFn } from '@angular/forms';
+
+/**
+ * Email validation pattern that matches standard email format.
+ * More strict than HTML5 default email validation.
+ */
+const EMAIL_PATTERN = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
+
+/**
+ * Custom email validator that provides stricter validation than Angular's built-in.
+ * Validates format: local@domain.tld
+ *
+ * @returns ValidatorFn that returns null if valid, or { email: true } if invalid
+ *
+ * @example
+ * ```typescript
+ * this.form = this.fb.group({
+ *   email: ['', [Validators.required, emailValidator()]]
+ * });
+ * ```
+ */
+export function emailValidator(): ValidatorFn {
+  return (control: AbstractControl): ValidationErrors | null => {
+    if (!control.value) {
+      return null; // Let required validator handle empty values
+    }
+    const isValid = EMAIL_PATTERN.test(control.value);
+    return isValid ? null : { email: true };
+  };
+}

src/frontend/src/app/shared/validators/index.ts

@@ -0,0 +1,2 @@
+export * from './email.validator';
+export * from './name.validator';

src/frontend/src/app/shared/validators/name.validator.ts

@@ -0,0 +1,64 @@
+import { AbstractControl, ValidationErrors, ValidatorFn } from '@angular/forms';
+
+/**
+ * Name validation options.
+ */
+export interface NameValidatorOptions {
+  /** Minimum length required (default: 3) */
+  minLength?: number;
+  /** Maximum length allowed (default: 100) */
+  maxLength?: number;
+  /** Whether to allow numbers (default: false) */
+  allowNumbers?: boolean;
+}
+
+const DEFAULT_OPTIONS: Required<NameValidatorOptions> = {
+  minLength: 3,
+  maxLength: 100,
+  allowNumbers: false,
+};
+
+/**
+ * Custom name validator with configurable options.
+ * Validates that name contains only letters, spaces, and common punctuation.
+ *
+ * @param options - Validation options
+ * @returns ValidatorFn that returns validation errors or null
+ *
+ * @example
+ * ```typescript
+ * this.form = this.fb.group({
+ *   name: ['', [Validators.required, nameValidator({ minLength: 2 })]]
+ * });
+ * ```
+ */
+export function nameValidator(options: NameValidatorOptions = {}): ValidatorFn {
+  const opts = { ...DEFAULT_OPTIONS, ...options };
+
+  return (control: AbstractControl): ValidationErrors | null => {
+    if (!control.value) {
+      return null; // Let required validator handle empty values
+    }
+
+    const value = control.value.trim();
+
+    if (value.length < opts.minLength) {
+      return { minlength: { requiredLength: opts.minLength, actualLength: value.length } };
+    }
+
+    if (value.length > opts.maxLength) {
+      return { maxlength: { requiredLength: opts.maxLength, actualLength: value.length } };
+    }
+
+    // Pattern: letters (including accented), spaces, hyphens, apostrophes
+    const pattern = opts.allowNumbers
+      ? /^[a-zA-ZáéíóúÁÉÍÓÚñÑüÜ0-9\s'-]+$/
+      : /^[a-zA-ZáéíóúÁÉÍÓÚñÑüÜ\s'-]+$/;
+
+    if (!pattern.test(value)) {
+      return { pattern: true };
+    }
+
+    return null;
+  };
+}