feat: add user role field and implement Gravatar fallback for user avatars

apps/frontend/src/lib/auth.tsx

@@ -40,6 +40,80 @@ export type AuthContextValue = {
 
 const AuthContext = createContext<AuthContextValue | null>(null);
 
+/**
+ * Standard MD5 implementation for Gravatar support
+ * (Self-contained to avoid dependency issues)
+ */
+function md5(string: string) {
+  const k = Array.from({ length: 64 }, (_, i) => Math.floor(Math.abs(Math.sin(i + 1)) * 2 ** 32));
+  let a = 0x67452301;
+  let b = 0xefcdab89;
+  let c = 0x98badcfe;
+  let d = 0x10325476;
+  const s = [
+    7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14,
+    20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10,
+    15, 21, 6, 10, 15, 21, 6, 10, 15, 21,
+  ];
+
+  const str = unescape(encodeURIComponent(string));
+  const msg = new Uint8Array(str.length);
+  for (let i = 0; i < str.length; i++) msg[i] = str.charCodeAt(i);
+
+  const len = msg.length;
+  const wordLen = ((len + 8) >> 6) + 1;
+  const words = new Uint32Array(wordLen * 16);
+  for (let i = 0; i < len; i++) words[i >> 2] |= msg[i] << ((i % 4) * 8);
+  words[len >> 2] |= 0x80 << ((len % 4) * 8);
+  words[wordLen * 16 - 2] = len * 8;
+
+  for (let i = 0; i < words.length; i += 16) {
+    let [aa, bb, cc, dd] = [a, b, c, d];
+    for (let j = 0; j < 64; j++) {
+      let f: number;
+      let g: number;
+      if (j < 16) {
+        f = (b & c) | (~b & d);
+        g = j;
+      } else if (j < 32) {
+        f = (d & b) | (~d & c);
+        g = (5 * j + 1) % 16;
+      } else if (j < 48) {
+        f = b ^ c ^ d;
+        g = (3 * j + 5) % 16;
+      } else {
+        f = c ^ (b | ~d);
+        g = (7 * j) % 16;
+      }
+      const temp = d;
+      d = c;
+      c = b;
+      b =
+        (b +
+          ((a + f + k[j] + words[i + g]) << s[j] | (a + f + k[j] + words[i + g]) >>> (32 - s[j]))) |
+        0;
+      a = temp;
+    }
+    a = (a + aa) | 0;
+    b = (b + bb) | 0;
+    c = (c + cc) | 0;
+    d = (d + dd) | 0;
+  }
+
+  return [a, b, c, d]
+    .map((v) =>
+      Array.from({ length: 4 }, (_, i) => ((v >> (i * 8)) & 0xff).toString(16).padStart(2, '0')).join(
+        ''
+      )
+    )
+    .join('');
+}
+
+function getGravatarUrl(email: string): string {
+  const hash = md5(email.trim().toLowerCase());
+  return `https://www.gravatar.com/avatar/${hash}?d=identicon`;
+}
+
 function getDisplayName(user: User | null): string {
   if (!user) return 'Usuario';
   if (user.name?.trim()) return user.name.trim();
@@ -53,7 +127,8 @@ function getInitials(name: string): string {
 }
 
 function getAvatarUrl(user: User | null): string | null {
-  return user?.image || null;
+  if (!user) return null;
+  return user.image || getGravatarUrl(user.email);
 }
 
 export function AuthProvider({ children }: PropsWithChildren) {