chore: add aibridge configs & experiment (#19793)

cli/testdata/server-config.yaml.golden

@@ -713,3 +713,20 @@ workspace_prebuilds:
   # limit; disabled when set to zero.
   # (default: 3, type: int)
   failure_hard_limit: 3
+aibridge:
+  # Whether to start an in-memory aibridged instance ("aibridge" experiment must be
+  # enabled, too).
+  # (default: false, type: bool)
+  enabled: false
+  # The base URL of the OpenAI API.
+  # (default: https://api.openai.com/v1/, type: string)
+  openai_base_url: https://api.openai.com/v1/
+  # The key to authenticate against the OpenAI API.
+  # (default: <unset>, type: string)
+  openai_key: ""
+  # The base URL of the Anthropic API.
+  # (default: https://api.anthropic.com/, type: string)
+  base_url: https://api.anthropic.com/
+  # The key to authenticate against the Anthropic API.
+  # (default: <unset>, type: string)
+  key: ""