deps: Upgrade snowflake-connector-python to 4.0.0

Upgrades from 3.18.0 to 4.0.0 to benefit from:
- Improved token expiration handling
- Certificate revocation checking via CRLs
- General stability improvements

Test results show +1 test passing (19 passed, 11 failed, up from 18/12).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: fordN

pyproject.toml

@@ -54,7 +54,7 @@ iceberg = [
 ]
 
 snowflake = [
-    "snowflake-connector-python>=3.5.0",
+    "snowflake-connector-python>=4.0.0",
     "snowpipe-streaming>=1.0.0",  # Snowpipe Streaming API
 ]
 
@@ -68,7 +68,7 @@ all_loaders = [
     "deltalake>=1.0.2",             # Delta Lake (consistent version)
     "pyiceberg[sql-sqlite]>=0.10.0", # Apache Iceberg
     "pydantic>=2.0,<2.12",          # PyIceberg 0.10.0 compatibility
-    "snowflake-connector-python>=3.5.0",  # Snowflake
+    "snowflake-connector-python>=4.0.0",  # Snowflake
     "snowpipe-streaming>=1.0.0",        # Snowpipe Streaming API
     "lmdb>=1.4.0",                  # LMDB
 ]