chore: remove aibridge experiment (#20520)

Removes the experiment and all references to it

cli/testdata/coder_server_--help.golden

@@ -80,6 +80,41 @@ OPTIONS:
           Periodically check for new releases of Coder and inform the owner. The
           check is performed once per day.
 
+AIBRIDGE OPTIONS: 
+      --aibridge-anthropic-base-url string, $CODER_AIBRIDGE_ANTHROPIC_BASE_URL (default: https://api.anthropic.com/)
+          The base URL of the Anthropic API.
+
+      --aibridge-anthropic-key string, $CODER_AIBRIDGE_ANTHROPIC_KEY
+          The key to authenticate against the Anthropic API.
+
+      --aibridge-bedrock-access-key string, $CODER_AIBRIDGE_BEDROCK_ACCESS_KEY
+          The access key to authenticate against the AWS Bedrock API.
+
+      --aibridge-bedrock-access-key-secret string, $CODER_AIBRIDGE_BEDROCK_ACCESS_KEY_SECRET
+          The access key secret to use with the access key to authenticate
+          against the AWS Bedrock API.
+
+      --aibridge-bedrock-model string, $CODER_AIBRIDGE_BEDROCK_MODEL (default: global.anthropic.claude-sonnet-4-5-20250929-v1:0)
+          The model to use when making requests to the AWS Bedrock API.
+
+      --aibridge-bedrock-region string, $CODER_AIBRIDGE_BEDROCK_REGION
+          The AWS Bedrock API region.
+
+      --aibridge-bedrock-small-fastmodel string, $CODER_AIBRIDGE_BEDROCK_SMALL_FAST_MODEL (default: global.anthropic.claude-haiku-4-5-20251001-v1:0)
+          The small fast model to use when making requests to the AWS Bedrock
+          API. Claude Code uses Haiku-class models to perform background tasks.
+          See
+          https://docs.claude.com/en/docs/claude-code/settings#environment-variables.
+
+      --aibridge-enabled bool, $CODER_AIBRIDGE_ENABLED (default: false)
+          Whether to start an in-memory aibridged instance.
+
+      --aibridge-openai-base-url string, $CODER_AIBRIDGE_OPENAI_BASE_URL (default: https://api.openai.com/v1/)
+          The base URL of the OpenAI API.
+
+      --aibridge-openai-key string, $CODER_AIBRIDGE_OPENAI_KEY
+          The key to authenticate against the OpenAI API.
+
 CLIENT OPTIONS: 
 These options change the behavior of how clients interact with the Coder.
 Clients include the Coder CLI, Coder Desktop, IDE extensions, and the web UI.

cli/testdata/server-config.yaml.golden

@@ -714,8 +714,7 @@ workspace_prebuilds:
   # (default: 3, type: int)
   failure_hard_limit: 3
 aibridge:
-  # Whether to start an in-memory aibridged instance ("aibridge" experiment must be
-  # enabled, too).
+  # Whether to start an in-memory aibridged instance.
   # (default: false, type: bool)
   enabled: false
   # The base URL of the OpenAI API.