remove "display name" from adding new friends

src-tauri/migrations/20260827000000_allow_unknown_friend_profiles.sql

@@ -0,0 +1,13 @@
+CREATE TABLE friends_with_optional_profiles (
+    id TEXT PRIMARY KEY NOT NULL,
+    display_name TEXT
+);
+
+-- Existing names were entered locally and cannot be distinguished from names
+-- learned from a signed remote profile. Keep the relationship, then learn the
+-- authoritative display name again from the remote.
+INSERT INTO friends_with_optional_profiles (id)
+SELECT id FROM friends;
+
+DROP TABLE friends;
+ALTER TABLE friends_with_optional_profiles RENAME TO friends;