fix: improve blockchain node RPC responses and database path consistency

- Add transaction data to RPC responses (get_block, get_blocks_range)
- Fix import_block to handle transactions parameter
- Change database paths to absolute paths for consistency
- Make dev_heartbeat.py executable

apps/coordinator-api/src/app/database.py

@@ -2,13 +2,14 @@
 
 from sqlmodel import create_engine, SQLModel
 from sqlalchemy import StaticPool
+from .config import settings
 
-# Create in-memory SQLite database for now
+# Create database engine using URL from config
 engine = create_engine(
-    "sqlite:///./data/coordinator.db",
-    connect_args={"check_same_thread": False},
-    poolclass=StaticPool,
-    echo=True  # Enable SQL logging for debugging
+    settings.database_url,
+    connect_args={"check_same_thread": False} if settings.database_url.startswith("sqlite") else {},
+    poolclass=StaticPool if settings.database_url.startswith("sqlite") else None,
+    echo=settings.test_mode  # Enable SQL logging for debugging in test mode
 )