fix(deps): switch to psycopg3 for Python 3.14 compatibility

psycopg2 is a C extension that requires libpq, which is incompatible
with python_abi 3.14 cp314t on conda-forge. psycopg (v3) is a pure
Python driver that works on all Python versions.

- Replace psycopg2 with psycopg in environment files
- Remove postgresql server package (pytest-postgresql manages its own)
- Update SQLAlchemy dialect from postgresql+psycopg2 to postgresql+psycopg

Author: vringar

environment.yaml

@@ -18,9 +18,8 @@ dependencies:
 - pillow=12.1.1
 - pip=26.0.1
 - plyvel=1.5.1
-- postgresql=17.9
 - pre-commit=4.5.1
-- psycopg2=2.9.11
+- psycopg=3.3.3
 - psutil=7.2.2
 - pyarrow=23.0.1
 - pytest-asyncio=1.3.0

scripts/environment-unpinned.yaml

@@ -15,8 +15,7 @@ dependencies:
     - pandas
     - pip
     - pillow
-    - postgresql
-    - psycopg2
+    - psycopg
     - plyvel
     - psutil
     - pytest-postgresql

test/storage/fixtures.py

@@ -49,7 +49,7 @@ def structured_provider(
         pg = request.getfixturevalue("postgresql")
         info = pg.info
         pg_url = (
-            f"postgresql+psycopg2://{info.user}:{info.password or ''}"
+            f"postgresql+psycopg://{info.user}:{info.password or ''}"
             f"@{info.host}:{info.port}/{info.dbname}"
         )
         return SQLAlchemyStorageProvider(pg_url)