Replace MLflow inline pip hack with proper Dockerfile

Add services/mlflow/Dockerfile that extends the official image with
psycopg2-binary, and point docker-compose to build from it.

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

docker-compose.yml

@@ -63,15 +63,12 @@ services:
       start_period: 40s
 
   mlflow:
-    image: ghcr.io/mlflow/mlflow:v2.10.0
+    build: ./services/mlflow
     ports:
       - "127.0.0.1:5000:5000"
     volumes:
       - mlflow-data:/mlflow
-    entrypoint: ["/bin/sh", "-c"]
-    command:
-      - |
-        pip install --quiet psycopg2-binary &&
+    command: >
       mlflow server
         --backend-store-uri "postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}"
         --default-artifact-root /mlflow/artifacts

services/mlflow/Dockerfile

@@ -0,0 +1,3 @@
+FROM ghcr.io/mlflow/mlflow:v2.10.0
+
+RUN pip install --no-cache-dir psycopg2-binary