fix: show pip install errors in start.bat and loosen dependency pins for Python 3.13+

start.bat was silently swallowing pip errors. Strict version pins on
pydantic, fastapi, and uvicorn caused build failures on Python 3.13+
due to missing pre-built wheels.

backend/requirements.txt

@@ -1,11 +1,11 @@
-fastapi==0.103.1
-uvicorn==0.23.2
+fastapi>=0.103.1
+uvicorn>=0.23.2
 yfinance>=0.2.40
 feedparser==6.0.10
 requests==2.31.0
 apscheduler==3.10.3
-pydantic==2.3.0
-pydantic-settings==2.0.3
+pydantic>=2.3.0
+pydantic-settings>=2.0.3
 playwright>=1.58.0
 beautifulsoup4>=4.12.0
 cachetools>=5.3

start.bat

@@ -12,7 +12,7 @@ if not exist "venv\" (
     python -m venv venv
 )
 call venv\Scripts\activate.bat
-pip install -r requirements.txt >nul 2>&1
+pip install -r requirements.txt
 cd ..
 
 echo.