fix(deps): override python-dotenv to >=1.2.2 to resolve GHSA-mf9w-mj56-hr94

litellm (transitive via ai-agent-contracts) pins python-dotenv to ~=1.0.1;
add a uv override to force the patched version across all extras.
Also upgrades python-multipart 0.0.24 -> 0.0.26 (GHSA-mj87-hwqh-73pj).

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

Author: flyersworder

pyproject.toml

@@ -83,6 +83,11 @@ select = ["E", "F", "I", "UP"]
 # demo-query strings; readability outweighs E501 line-length here.
 "examples/**" = ["E501"]
 
+[tool.uv]
+override-dependencies = [
+    "python-dotenv>=1.2.2",
+]
+
 [tool.ty.environment]
 python-version = "3.12"