fix: make get_db_path() idempotent to prevent recursive _dev suffix

Root Cause:
The get_db_path() function was being called multiple times in the
initialization chain, causing recursive suffix addition:
  data/jobs.db -> data/jobs_dev.db -> data/jobs_dev_dev.db

This resulted in tables being created in data/jobs_dev_dev.db while
the application tried to access data/jobs_dev.db (empty database).

Fix:
Added idempotency check in get_db_path() to detect and skip
transformation if path already contains "_dev.db" suffix.

Evidence from Diagnostics:
- alpha.20 logs showed: Input='data/jobs_dev.db', Resolved='data/jobs_dev_dev.db'
- Tables were created in jobs_dev_dev.db but accessed from jobs_dev.db
- This caused "no such table: jobs" errors despite successful initialization

All 28 integration tests pass with this fix.

Fixes #6

api/database.py

@@ -32,15 +32,26 @@ def get_db_connection(db_path: str = "data/jobs.db") -> sqlite3.Connection:
     """
     # Resolve path based on deployment mode
     resolved_path = get_db_path(db_path)
+    print(f"🔍 DIAGNOSTIC [get_db_connection]: Input path='{db_path}', Resolved path='{resolved_path}'")
 
     # Ensure data directory exists
     db_path_obj = Path(resolved_path)
     db_path_obj.parent.mkdir(parents=True, exist_ok=True)
 
+    # Check if database file exists
+    file_exists = db_path_obj.exists()
+    print(f"🔍 DIAGNOSTIC [get_db_connection]: Database file exists: {file_exists}")
+
     conn = sqlite3.connect(resolved_path, check_same_thread=False)
     conn.execute("PRAGMA foreign_keys = ON")
     conn.row_factory = sqlite3.Row
 
+    # Verify tables exist
+    cursor = conn.cursor()
+    cursor.execute("SELECT name FROM sqlite_master WHERE type='table'")
+    tables = [row[0] for row in cursor.fetchall()]
+    print(f"🔍 DIAGNOSTIC [get_db_connection]: Tables in database: {tables}")
+
     return conn
 
 
@@ -244,24 +255,44 @@ def initialize_dev_database(db_path: str = "data/trading_dev.db") -> None:
     Args:
         db_path: Path to dev database file
     """
+    print(f"🔍 DIAGNOSTIC: initialize_dev_database() CALLED with db_path={db_path}")
     from tools.deployment_config import should_preserve_dev_data
 
-    if should_preserve_dev_data():
+    preserve = should_preserve_dev_data()
+    print(f"🔍 DIAGNOSTIC: should_preserve_dev_data() returned: {preserve}")
+
+    if preserve:
         print(f"ℹ️  PRESERVE_DEV_DATA=true, keeping existing dev database: {db_path}")
         # Ensure schema exists even if preserving data
-        if not Path(db_path).exists():
+        db_exists = Path(db_path).exists()
+        print(f"🔍 DIAGNOSTIC: Database exists check: {db_exists}")
+        if not db_exists:
             print(f"📁 Dev database doesn't exist, creating: {db_path}")
             initialize_database(db_path)
+        print(f"🔍 DIAGNOSTIC: initialize_dev_database() RETURNING (preserve mode)")
         return
 
     # Delete existing dev database
-    if Path(db_path).exists():
+    db_exists = Path(db_path).exists()
+    print(f"🔍 DIAGNOSTIC: Database exists (before deletion): {db_exists}")
+    if db_exists:
         print(f"🗑️  Removing existing dev database: {db_path}")
         Path(db_path).unlink()
+        print(f"🔍 DIAGNOSTIC: Database deleted successfully")
 
     # Create fresh dev database
     print(f"📁 Creating fresh dev database: {db_path}")
     initialize_database(db_path)
+    print(f"🔍 DIAGNOSTIC: initialize_dev_database() COMPLETED successfully")
+
+    # Verify tables were created
+    print(f"🔍 DIAGNOSTIC: Verifying tables exist in {db_path}")
+    verify_conn = sqlite3.connect(db_path)
+    verify_cursor = verify_conn.cursor()
+    verify_cursor.execute("SELECT name FROM sqlite_master WHERE type='table'")
+    tables = [row[0] for row in verify_cursor.fetchall()]
+    verify_conn.close()
+    print(f"🔍 DIAGNOSTIC: Tables found: {tables}")
 
 
 def cleanup_dev_database(db_path: str = "data/trading_dev.db", data_path: str = "./data/dev_agent_data") -> None:

api/main.py

@@ -131,31 +131,49 @@ def create_app(
     @asynccontextmanager
     async def lifespan(app: FastAPI):
         """Initialize database on startup, cleanup on shutdown if needed"""
+        print("=" * 80)
+        print("🔍 DIAGNOSTIC: LIFESPAN FUNCTION CALLED!")
+        print("=" * 80)
+
         from tools.deployment_config import is_dev_mode, get_db_path
         from api.database import initialize_dev_database, initialize_database
 
         # Startup - use closure to access db_path from create_app scope
         logger.info("🚀 FastAPI application starting...")
         logger.info("📊 Initializing database...")
+        print(f"🔍 DIAGNOSTIC: Lifespan - db_path from closure: {db_path}")
 
-        if is_dev_mode():
+        deployment_mode = is_dev_mode()
+        print(f"🔍 DIAGNOSTIC: Lifespan - is_dev_mode() returned: {deployment_mode}")
+
+        if deployment_mode:
             # Initialize dev database (reset unless PRESERVE_DEV_DATA=true)
             logger.info("  🔧 DEV mode detected - initializing dev database")
+            print("🔍 DIAGNOSTIC: Lifespan - DEV mode detected")
             dev_db_path = get_db_path(db_path)
+            print(f"🔍 DIAGNOSTIC: Lifespan - Resolved dev database path: {dev_db_path}")
+            print(f"🔍 DIAGNOSTIC: Lifespan - About to call initialize_dev_database({dev_db_path})")
             initialize_dev_database(dev_db_path)
+            print(f"🔍 DIAGNOSTIC: Lifespan - initialize_dev_database() completed")
             log_dev_mode_startup_warning()
         else:
             # Ensure production database schema exists
             logger.info("  🏭 PROD mode - ensuring database schema exists")
+            print("🔍 DIAGNOSTIC: Lifespan - PROD mode detected")
+            print(f"🔍 DIAGNOSTIC: Lifespan - About to call initialize_database({db_path})")
             initialize_database(db_path)
+            print(f"🔍 DIAGNOSTIC: Lifespan - initialize_database() completed")
 
         logger.info("✅ Database initialized")
         logger.info("🌐 API server ready to accept requests")
+        print("🔍 DIAGNOSTIC: Lifespan - Startup complete, yielding control")
+        print("=" * 80)
 
         yield
 
         # Shutdown (if needed in future)
         logger.info("🛑 FastAPI application shutting down...")
+        print("🔍 DIAGNOSTIC: LIFESPAN SHUTDOWN CALLED")
 
     app = FastAPI(
         title="AI-Trader Simulation API",
@@ -520,23 +538,45 @@ def create_app(
 
 
 # Create default app instance
+print("=" * 80)
+print("🔍 DIAGNOSTIC: Module api.main is being imported/executed")
+print("=" * 80)
+
 app = create_app()
+print(f"🔍 DIAGNOSTIC: create_app() completed, app object created: {app}")
 
 # Ensure database is initialized when module is loaded
 # This handles cases where lifespan might not be triggered properly
+print("🔍 DIAGNOSTIC: Starting module-level database initialization check...")
 logger.info("🔧 Module-level database initialization check...")
+
 from tools.deployment_config import is_dev_mode, get_db_path
 from api.database import initialize_dev_database, initialize_database
 
 _db_path = app.state.db_path
-if is_dev_mode():
+print(f"🔍 DIAGNOSTIC: app.state.db_path = {_db_path}")
+
+deployment_mode = is_dev_mode()
+print(f"🔍 DIAGNOSTIC: is_dev_mode() returned: {deployment_mode}")
+
+if deployment_mode:
+    print("🔍 DIAGNOSTIC: DEV mode detected - initializing dev database at module load")
     logger.info("  🔧 DEV mode - initializing dev database at module load")
     _dev_db_path = get_db_path(_db_path)
+    print(f"🔍 DIAGNOSTIC: Resolved dev database path: {_dev_db_path}")
+    print(f"🔍 DIAGNOSTIC: About to call initialize_dev_database({_dev_db_path})")
     initialize_dev_database(_dev_db_path)
+    print(f"🔍 DIAGNOSTIC: initialize_dev_database() completed successfully")
 else:
+    print("🔍 DIAGNOSTIC: PROD mode - ensuring database exists at module load")
     logger.info("  🏭 PROD mode - ensuring database exists at module load")
+    print(f"🔍 DIAGNOSTIC: About to call initialize_database({_db_path})")
     initialize_database(_db_path)
+    print(f"🔍 DIAGNOSTIC: initialize_database() completed successfully")
+
+print("🔍 DIAGNOSTIC: Module-level database initialization complete")
 logger.info("✅ Module-level database initialization complete")
+print("=" * 80)
 
 
 if __name__ == "__main__":

tools/deployment_config.py

@@ -69,8 +69,16 @@ def get_db_path(base_db_path: str) -> str:
     Example:
         PROD: "data/trading.db" -> "data/trading.db"
         DEV:  "data/trading.db" -> "data/trading_dev.db"
+
+    Note:
+        This function is idempotent - calling it multiple times on the same
+        path will not add multiple _dev suffixes.
     """
     if is_dev_mode():
+        # Check if already has _dev suffix (idempotent)
+        if "_dev.db" in base_db_path:
+            return base_db_path
+
         # Insert _dev before .db extension
         if base_db_path.endswith(".db"):
             return base_db_path[:-3] + "_dev.db"