replace custom validation with Zod

package-lock.json

···
         "jszip": "^3.10.1",
         "lucide-react": "^0.544.0",
         "react": "^18.3.1",
-        "react-dom": "^18.3.1"
+        "react-dom": "^18.3.1",
+        "zod": "^4.2.1"
       },
       "devDependencies": {
         "@types/jszip": "^3.4.0",
···
         "zod": "^3.23.8"
       }
     },
+    "node_modules/@atproto-labs/did-resolver/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto-labs/fetch": {
       "version": "0.2.3",
       "resolved": "https://registry.npmjs.org/@atproto-labs/fetch/-/fetch-0.2.3.tgz",
···
         "node": ">=18.7.0"
       }
     },
+    "node_modules/@atproto-labs/handle-resolver/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto-labs/identity-resolver": {
       "version": "0.3.1",
       "resolved": "https://registry.npmjs.org/@atproto-labs/identity-resolver/-/identity-resolver-0.3.1.tgz",
···
         "zod": "^3.23.8"
       }
     },
+    "node_modules/@atproto/api/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto/common-web": {
       "version": "0.4.3",
       "resolved": "https://registry.npmjs.org/@atproto/common-web/-/common-web-0.4.3.tgz",
···
         "multiformats": "^9.9.0",
         "uint8arrays": "3.0.0",
         "zod": "^3.23.8"
+      }
+    },
+    "node_modules/@atproto/common-web/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
       }
     },
     "node_modules/@atproto/crypto": {
···
         "zod": "^3.23.8"
       }
     },
+    "node_modules/@atproto/did/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto/identity": {
       "version": "0.4.9",
       "resolved": "https://registry.npmjs.org/@atproto/identity/-/identity-0.4.9.tgz",
···
         "zod": "^3.23.8"
       }
     },
+    "node_modules/@atproto/jwk-webcrypto/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
+    "node_modules/@atproto/jwk/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto/lexicon": {
       "version": "0.5.1",
       "resolved": "https://registry.npmjs.org/@atproto/lexicon/-/lexicon-0.5.1.tgz",
···
         "iso-datestring-validator": "^2.2.2",
         "multiformats": "^9.9.0",
         "zod": "^3.23.8"
+      }
+    },
+    "node_modules/@atproto/lexicon/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
       }
     },
     "node_modules/@atproto/oauth-client": {
···
         "node": ">=18.7.0"
       }
     },
+    "node_modules/@atproto/oauth-client/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto/oauth-types": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/@atproto/oauth-types/-/oauth-types-0.4.1.tgz",
···
         "zod": "^3.23.8"
       }
     },
+    "node_modules/@atproto/oauth-types/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
+      }
+    },
     "node_modules/@atproto/syntax": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/@atproto/syntax/-/syntax-0.4.1.tgz",
···
       "dependencies": {
         "@atproto/lexicon": "^0.5.1",
         "zod": "^3.23.8"
+      }
+    },
+    "node_modules/@atproto/xrpc/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
       }
     },
     "node_modules/@babel/code-frame": {
···
       },
       "engines": {
         "node": ">=10"
+      }
+    },
+    "node_modules/@netlify/zip-it-and-ship-it/node_modules/zod": {
+      "version": "3.25.76",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
+      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/colinhacks"
       }
     },
     "node_modules/@noble/curves": {
···
       }
     },
     "node_modules/zod": {
-      "version": "3.25.76",
-      "resolved": "https://registry.npmjs.org/zod/-/zod-3.25.76.tgz",
-      "integrity": "sha512-gzUt/qt81nXsFGKIFcC3YnfEAx5NkunCfnDlvuBSSFS02bcXu4Lmea0AFIUwbLWxWPx3d9p8S5QoaujKcNQxcQ==",
+      "version": "4.2.1",
+      "resolved": "https://registry.npmjs.org/zod/-/zod-4.2.1.tgz",
+      "integrity": "sha512-0wZ1IRqGGhMP76gLqz8EyfBXKk0J2qo2+H3fi4mcUP/KtTocoX08nmIAHl1Z2kJIZbZee8KOpBCSNPRgauucjw==",
       "license": "MIT",
       "funding": {
         "url": "https://github.com/sponsors/colinhacks"

package.json

···
     "jszip": "^3.10.1",
     "lucide-react": "^0.544.0",
     "react": "^18.3.1",
-    "react-dom": "^18.3.1"
+    "react-dom": "^18.3.1",
+    "zod": "^4.2.1"
   },
   "devDependencies": {
     "@types/jszip": "^3.4.0",

src/lib/validation.ts

···
 /**
- * Validation utilities for forms
+ * Validation utilities using Zod schemas
  */
+import { z } from "zod";
 
 export interface ValidationResult {
   isValid: boolean;
···
 }
 
 /**
- * Validate AT Protocol handle
+ * Helper to convert Zod validation to ValidationResult
  */
-export function validateHandle(handle: string): ValidationResult {
-  const trimmed = handle.trim();
-
-  if (!trimmed) {
-    return {
-      isValid: false,
-      error: "Please enter your handle",
-    };
-  }
-
-  // Remove @ if user included it
-  const cleanHandle = trimmed.startsWith("@") ? trimmed.slice(1) : trimmed;
-
-  // Basic format validation
-  if (cleanHandle.length < 3) {
-    return {
-      isValid: false,
-      error: "Handle is too short",
-    };
-  }
-
-  // Check for valid characters (alphanumeric, dots, hyphens)
-  const validFormat = /^[a-zA-Z0-9.-]+$/;
-  if (!validFormat.test(cleanHandle)) {
-    return {
-      isValid: false,
-      error: "Handle contains invalid characters",
-    };
+function validateWithZod<T>(
+  schema: z.ZodSchema<T>,
+  value: unknown,
+): ValidationResult {
+  const result = schema.safeParse(value);
+  if (result.success) {
+    return { isValid: true };
   }
+  return {
+    isValid: false,
+    error: result.error.errors[0]?.message || "Validation failed",
+  };
+}
 
-  // Must contain at least one dot (domain required)
-  if (!cleanHandle.includes(".")) {
-    return {
-      isValid: false,
-      error: "Handle must include a domain (e.g., username.bsky.social)",
-    };
-  }
+/**
+ * Zod Schemas
+ */
+const handleSchema = z
+  .string()
+  .trim()
+  .min(1, "Please enter your handle")
+  .transform((val) => (val.startsWith("@") ? val.slice(1) : val))
+  .pipe(
+    z
+      .string()
+      .min(3, "Handle is too short")
+      .regex(/^[a-zA-Z0-9.-]+$/, "Handle contains invalid characters")
+      .refine((val) => val.includes("."), {
+        message: "Handle must include a domain (e.g., username.bsky.social)",
+      })
+      .refine((val) => !/^[.-]|[.-]$/.test(val), {
+        message: "Handle cannot start or end with . or -",
+      }),
+  );
 
-  // Can't start or end with dot or hyphen
-  if (/^[.-]|[.-]$/.test(cleanHandle)) {
-    return {
-      isValid: false,
-      error: "Handle cannot start or end with . or -",
-    };
-  }
+const emailSchema = z
+  .string()
+  .trim()
+  .min(1, "Please enter your email")
+  .email("Please enter a valid email address");
 
-  return { isValid: true };
+/**
+ * Validate AT Protocol handle
+ */
+export function validateHandle(handle: string): ValidationResult {
+  return validateWithZod(handleSchema, handle);
 }
 
 /**
  * Validate email format
  */
 export function validateEmail(email: string): ValidationResult {
-  const trimmed = email.trim();
-
-  if (!trimmed) {
-    return {
-      isValid: false,
-      error: "Please enter your email",
-    };
-  }
-
-  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
-  if (!emailRegex.test(trimmed)) {
-    return {
-      isValid: false,
-      error: "Please enter a valid email address",
-    };
-  }
-
-  return { isValid: true };
+  return validateWithZod(emailSchema, email);
 }
 
 /**
···
   value: string,
   fieldName: string = "This field",
 ): ValidationResult {
-  const trimmed = value.trim();
-
-  if (!trimmed) {
-    return {
-      isValid: false,
-      error: `${fieldName} is required`,
-    };
-  }
-
-  return { isValid: true };
+  const schema = z.string().trim().min(1, `${fieldName} is required`);
+  return validateWithZod(schema, value);
 }
 
 /**
···
   minLength: number,
   fieldName: string = "This field",
 ): ValidationResult {
-  const trimmed = value.trim();
-
-  if (trimmed.length < minLength) {
-    return {
-      isValid: false,
-      error: `${fieldName} must be at least ${minLength} characters`,
-    };
-  }
-
-  return { isValid: true };
+  const schema = z
+    .string()
+    .trim()
+    .min(minLength, `${fieldName} must be at least ${minLength} characters`);
+  return validateWithZod(schema, value);
 }
 
 /**
···
   maxLength: number,
   fieldName: string = "This field",
 ): ValidationResult {
-  if (value.length > maxLength) {
-    return {
-      isValid: false,
-      error: `${fieldName} must be ${maxLength} characters or less`,
-    };
-  }
+  const schema = z
+    .string()
+    .max(maxLength, `${fieldName} must be ${maxLength} characters or less`);
+  return validateWithZod(schema, value);
+}
 
-  return { isValid: true };
-}
+/**
+ * Export schemas for advanced usage
+ */
+export const schemas = {
+  handle: handleSchema,
+  email: emailSchema,
+};