Add player profiles and community settings

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/migrations/015_player_identity.sql

@@ -0,0 +1,53 @@
+-- +mixmaker Up
+ALTER TABLE players
+    ADD COLUMN IF NOT EXISTS battle_tag text NOT NULL DEFAULT '';
+
+DO $$
+DECLARE
+    item record;
+    base_name text;
+    candidate text;
+    suffix text;
+    duplicate_number integer;
+BEGIN
+    FOR item IN SELECT id, display_name FROM players ORDER BY created_at, id LOOP
+        base_name := regexp_replace(item.display_name, '^[[:space:]]+|[[:space:]]+$', '', 'g');
+        IF char_length(base_name) < 2 THEN
+            base_name := 'Player';
+        END IF;
+        base_name := left(base_name, 32);
+        candidate := base_name;
+        duplicate_number := 1;
+        WHILE EXISTS (
+            SELECT 1 FROM players
+            WHERE id <> item.id AND lower(display_name) = lower(candidate)
+        ) LOOP
+            duplicate_number := duplicate_number + 1;
+            suffix := '-' || duplicate_number::text;
+            candidate := left(base_name, 32 - char_length(suffix)) || suffix;
+        END LOOP;
+        UPDATE players SET display_name = candidate WHERE id = item.id;
+    END LOOP;
+END $$;
+
+ALTER TABLE players
+    DROP CONSTRAINT IF EXISTS players_display_name_valid,
+    ADD CONSTRAINT players_display_name_valid CHECK (
+        display_name = regexp_replace(display_name, '^[[:space:]]+|[[:space:]]+$', '', 'g')
+        AND char_length(display_name) BETWEEN 2 AND 32
+    ),
+    DROP CONSTRAINT IF EXISTS players_battle_tag_valid,
+    ADD CONSTRAINT players_battle_tag_valid CHECK (
+        battle_tag = ''
+        OR battle_tag ~ '^[^#[:space:]]{2,20}#[0-9]{3,12}$'
+    );
+
+CREATE UNIQUE INDEX IF NOT EXISTS players_display_name_lower_uidx
+    ON players (lower(display_name));
+
+-- +mixmaker Down
+DROP INDEX IF EXISTS players_display_name_lower_uidx;
+ALTER TABLE players
+    DROP CONSTRAINT IF EXISTS players_battle_tag_valid,
+    DROP CONSTRAINT IF EXISTS players_display_name_valid,
+    DROP COLUMN IF EXISTS battle_tag;