fix(deps): bump python-dotenv to >=1.2.2 (CVE symlink overwrite)

Resolves last open Dependabot alert: python-dotenv symlink following
in set_key allows arbitrary file overwrite via cross-device rename.

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

requirements.txt

@@ -37,7 +37,7 @@ tables
 tree-sitter-python
 tree-sitter
 
-python-dotenv
+python-dotenv>=1.2.2  # CVE: symlink following allows arbitrary file overwrite
 
 # infrastructure related.
 docker