Chat plugin fails to compile with rollup plugin compiler: _assert is not a function

Contribute Bug
1

Since the rollup plugin compiler was enabled by default (#38658), the chat plugin fails to compile. The output chat_main.js contains:

throw new Error("[PLUGIN chat] Compile error: TypeError: Could not load discourse/plugins/chat/virtual:entrypoint:main: /discourse/plugins/chat/discourse/initializers/chat-sidebar.js: _assert is not a function");

Stack trace:
	JavaScript at ImportInjector._applyDefaults (asset-processor.js:73262:13)
	JavaScript at new ImportInjector (asset-processor.js:73240:36)           
	JavaScript at addNamed2 (asset-processor.js:73542:16)
	avaScript at File._addHelper (asset-processor.js:74980:25)

Environment: self-hosted, ./launcher rebuild app, base image 2.0.20260209-1300, all third-party plugins disabled.