feat: replace mail protocol with smolmail and rebuild the UI

lib/presentation/widgets/drawer/identity_header.dart

@@ -0,0 +1,64 @@
+import "package:flutter/material.dart";
+
+import "package:smol_mail/shared/utils/format.dart";
+
+/// Identity summary in the drawer: the address is what gets shared, the
+/// fingerprint is what gets verified.
+class IdentityHeader extends StatelessWidget {
+  final String address;
+  final String fingerprint;
+
+  const IdentityHeader({
+    super.key,
+    required this.address,
+    required this.fingerprint,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Column(
+      children: <Widget>[
+        CircleAvatar(
+          backgroundColor: Theme.of(context).primaryColor,
+          radius: 35,
+          child: Text(
+            address.isEmpty ? "?" : address[0].toUpperCase(),
+            style:
+                Theme.of(context).textTheme.bodyLarge!.copyWith(fontSize: 30),
+          ),
+        ),
+        const SizedBox(height: 20),
+        InkWell(
+          onTap: () => copyText(context, address),
+          child: Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 16),
+            child: Text(
+              address.isEmpty ? "(not registered)" : address,
+              overflow: TextOverflow.ellipsis,
+              style: const TextStyle(
+                fontSize: 18,
+                fontWeight: FontWeight.w900,
+              ),
+            ),
+          ),
+        ),
+        const SizedBox(height: 5),
+        InkWell(
+          onTap: () => copyText(context, fingerprint),
+          child: Padding(
+            padding: const EdgeInsets.symmetric(horizontal: 16),
+            child: Text(
+              "fp: $fingerprint",
+              overflow: TextOverflow.ellipsis,
+              style: TextStyle(
+                color: Theme.of(context).colorScheme.onSurfaceVariant,
+                fontSize: 14,
+                fontWeight: FontWeight.w700,
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}