stack/getpaid 2 55 nostr keys ux

lib/core/nostr/nostr_keychain_handle.dart

@@ -36,6 +36,9 @@ final class NostrKeychainHandle {
 
   String get publicKeyHex => _key.getPublic().toXOnlyHex();
 
+  /// NIP-19 `npub` display encoding of [publicKeyHex].
+  String get npub => NostrPublicKeyEncoding.npubFromPublicKeyHex(publicKeyHex);
+
   String signHashHex(String messageHashHex) {
     final digest = hex.decode(messageHashHex);
     if (digest.length != 32) {
@@ -98,6 +101,32 @@ void _validateNostrBip85Path(String hardenedPath) {
   }
 }
 
+/// NIP-19 bech32 display encoding for Nostr public keys.
+///
+/// A stored 32-byte x-only public key is never shown as hex in the UI: `npub`
+/// is the only representation users see, so every surface encodes through here
+/// instead of formatting the hex itself. Shares the bech32 encoder and bit
+/// converter used for `nsec`, so the two encodings cannot drift apart.
+final class NostrPublicKeyEncoding {
+  const NostrPublicKeyEncoding._();
+
+  static final _publicKeyHexPattern = RegExp(r'^[0-9a-fA-F]{64}$');
+
+  static String npubFromPublicKeyHex(String publicKeyHex) {
+    final normalized = publicKeyHex.trim().toLowerCase();
+    if (!_publicKeyHexPattern.hasMatch(normalized)) {
+      throw ArgumentError.value(
+        publicKeyHex,
+        'publicKeyHex',
+        'Nostr public key must be 32-byte hex',
+      );
+    }
+    return bech32.encode(
+      Bech32('npub', _convertBits(hex.decode(normalized), 8, 5, true)),
+    );
+  }
+}
+
 /// Secret materialization is deliberately a one-shot operation. Callers must
 /// not persist the returned value or place it in application state.
 final class NostrKeychainSecretMaterializer {

lib/core/storage/migrations/schema_19_to_20.dart

@@ -1,7 +1,11 @@
 import 'package:bb_mobile/core/storage/sqlite_database.steps.dart';
 import 'package:drift/drift.dart';
 
-/// Adds local metadata for materialized Nostr keys.
+/// Adds local metadata for materialized Nostr keys: public key, kind, purpose,
+/// and the optional user-authored description.
+///
+/// The table is created with its final version-20 shape, so there is no
+/// separate column-add step for `description`.
 class Schema19To20 {
   static Future<void> migrate(Migrator m, Schema20 schema20) async {
     await m.createTable(schema20.keychainManifestNostrKeys);

lib/core/storage/schemas/bull_database/drift_schema_v20.json

@@ -2223,6 +2223,16 @@
             "default_client_dart": null,
             "dsl_features": []
           },
+          {
+            "name": "description",
+            "getter_name": "description",
+            "moor_type": "string",
+            "nullable": true,
+            "customConstraints": null,
+            "default_dart": null,
+            "default_client_dart": null,
+            "dsl_features": []
+          },
           {
             "name": "created_at",
             "getter_name": "createdAt",
@@ -2681,7 +2691,7 @@
       "sql": [
         {
           "dialect": "sqlite",
-          "sql": "CREATE TABLE IF NOT EXISTS \"keychain_manifest_nostr_keys\" (\"entry_id\" TEXT NOT NULL, \"public_key_hex\" TEXT NOT NULL, \"key_kind\" TEXT NOT NULL, \"purpose\" TEXT NOT NULL, \"created_at\" INTEGER NOT NULL, \"updated_at\" INTEGER NOT NULL, PRIMARY KEY (\"entry_id\"));"
+          "sql": "CREATE TABLE IF NOT EXISTS \"keychain_manifest_nostr_keys\" (\"entry_id\" TEXT NOT NULL, \"public_key_hex\" TEXT NOT NULL, \"key_kind\" TEXT NOT NULL, \"purpose\" TEXT NOT NULL, \"description\" TEXT NULL, \"created_at\" INTEGER NOT NULL, \"updated_at\" INTEGER NOT NULL, PRIMARY KEY (\"entry_id\"));"
         }
       ]
     },