Add bidirectional host bridge

example/assets/games/template/scripts/runtime_defs.lua

@@ -69,6 +69,9 @@
 ---| 'network_ws_message'
 ---| 'network_ws_error'
 ---| 'network_ws_close'
+---| 'host_notify'
+---| 'host_call'
+---| 'host_call_result'
 
 ---@alias RuntimeScaleMode
 ---| 'fit'
@@ -598,6 +601,20 @@
 ---@field url string ws/wss URL.
 ---@field protocols? string[]
 
+---@class RuntimeHostCallOptions
+---@field id? string
+---@field method string Host method name registered by Flutter.
+---@field data? any
+
+---@class RuntimeHostNotifyOptions
+---@field method string Host notification name registered by Flutter.
+---@field data? any
+
+---@class RuntimeHostRespondOptions
+---@field id string Host-to-Lua call id from host_call event.
+---@field result? any
+---@field error? string
+
 ---@class RuntimeImportApi
 ---@field import fun(moduleName: string): table
 ---@field log fun(...: any)
@@ -605,6 +622,9 @@
 ---@field ws_connect fun(options: RuntimeWsConnectOptions): string Opens a WebSocket and returns connection id. Event types: network_ws_open/network_ws_message/network_ws_error/network_ws_close.
 ---@field ws_send fun(id: string, message: string): boolean
 ---@field ws_close fun(id: string): boolean
+---@field host_call fun(options: RuntimeHostCallOptions): string Starts an async Lua-to-Flutter host call. Result event type: host_call_result.
+---@field host_notify fun(options: RuntimeHostNotifyOptions): boolean Sends a fire-and-forget notification to Flutter host code.
+---@field host_respond fun(options: RuntimeHostRespondOptions): boolean Completes a Flutter-to-Lua host_call event.
 
 ---@type RuntimeImportApi
 runtime = runtime