Closes https://github.com/coder/internal/issues/988 The logic for allowing/denying tools can be found in https://github.com/coder/aibridge/pull/4/files#diff-330a6371a583dd8cadeed79b95499e3a87960ad8ea4d6a94061e8f88a44834c3 (`ProxyBase.filterAllowedTools`).
* chore: yaml parsing for external auth configs * Also unmarshal and check the output again