Fix OpenAI-compatible tool integration

[ThalesMMS]

Summary

• forward API-key environment variables referenced by models.json into the containerized shim without placing secret values in Docker arguments
• unwrap Grok Bot's nested jsonSchema tool parameters for OpenAI-compatible and Codex OAuth providers
• preserve assistant tool calls and tool results in OpenAI-compatible conversation history so completed actions do not repeat
• make model-catalog tests follow the configured default model
• add regression coverage for schema conversion, tool history, and provider environment forwarding

Verification

• npm ci
• npm test (7 passing)
• npm run check
• git diff HEAD^ HEAD --check

Stacking

This PR is based on luinbytes:setup/macos-grokbot-shim, the head branch of codeaashu/grokbot-shim#1. Merging it updates that parent PR with only the tool-integration fixes in commit ab0ef77.