chore: pin all Python dependency versions in requirements.txt (#64)

- Pin all 14 dependencies to exact versions (==)
- Remove duplicate python-multipart entry
- Upgrade numpy from floor constraint (<2) to exact pin (1.26.4, latest 1.x)
- Pin Dockerfile base image from :latest to :python3.11

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM tiangolo/uvicorn-gunicorn-fastapi:latest
+FROM tiangolo/uvicorn-gunicorn-fastapi:python3.11
 
 WORKDIR /usr/src/app
 

requirements.txt

@@ -1,15 +1,14 @@
-pydantic==1.*
-fastapi
-uvicorn
-peewee
-psycopg2-binary  # PostgreSQL adapter for Python
-python-multipart
-numpy<2
-pandas
-pygsheets
-pybaseball
-python-multipart
-requests
-html2image
-jinja2
-playwright
+pydantic==1.10.21
+fastapi==0.111.1
+uvicorn==0.30.6
+peewee==3.17.9
+psycopg2-binary==2.9.9
+python-multipart==0.0.9
+numpy==1.26.4
+pandas==2.2.3
+pygsheets==2.0.6
+pybaseball==2.2.7
+requests==2.32.3
+html2image==2.0.6
+jinja2==3.1.4
+playwright==1.45.1