Bump llm to 0.4.3

[casey-brooks]

Summary

• bump default llm_chart_version from 0.4.2 to 0.4.3
• 0.4.3 includes the LLM service authz tuple write on CreateModel, which is required for llm-proxy can_use checks against models created during E2E

Why

Chat-app E2E logs show llm-proxy 403s for API-token-authenticated agent processes:

principal_identity_type=user ... tuple_user=identity:<api-token-user> tuple_relation=can_use tuple_object=model:<model_id>
authorization denied

Those models resolve successfully in the LLM service, but OpenFGA has no organization:<org_id>, org, model:<model_id> tuple, so can_use: member from org cannot resolve. Bootstrap was still deploying llm chart 0.4.2; the tuple-write fix is in llm 0.4.3.

Tests

• terraform fmt -check -recursive