chore!: allow coder MCP tools to not be injected (#20713)

Currently, when AI Bridge is enabled AND the `oauth2` and
`mcp-server-http` experiments are enabled we inject Coder's MCP tools
into all intercepted AI Bridge requests.

This PR introduces a config to control this behaviour.

**NOTE:** this is a backwards-incompatible change; previously these
tools would be injected automatically, now this setting will need to be
explicitly enabled.

---------

Signed-off-by: Danny Kopping <danny@coder.com>

coderd/apidoc/docs.go

@@ -11700,6 +11700,9 @@ const docTemplate = `{
                 "enabled": {
                     "type": "boolean"
                 },
+                "inject_coder_mcp_tools": {
+                    "type": "boolean"
+                },
                 "openai": {
                     "$ref": "#/definitions/codersdk.AIBridgeOpenAIConfig"
                 }

coderd/apidoc/swagger.json

@@ -10396,6 +10396,9 @@
 				"enabled": {
 					"type": "boolean"
 				},
+				"inject_coder_mcp_tools": {
+					"type": "boolean"
+				},
 				"openai": {
 					"$ref": "#/definitions/codersdk.AIBridgeOpenAIConfig"
 				}