Add full monorepo: virtual-banker, backend, frontend, docs, scripts, deployment

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

backend/database/migrations/0002_backfill_checkpoints.up.sql

@@ -0,0 +1,9 @@
+-- Backfill checkpoints table for tracking backfill progress
+
+CREATE TABLE IF NOT EXISTS backfill_checkpoints (
+    chain_id INTEGER NOT NULL,
+    last_block BIGINT NOT NULL,
+    updated_at TIMESTAMP DEFAULT NOW(),
+    PRIMARY KEY (chain_id)
+);
+