chore: establish YCode replication baseline and TODO

scripts/test-terminal-host-plugin.ts

@@ -0,0 +1,14 @@
+import type { Plugin } from 'esbuild'
+
+/** Conversation suites never create native terminals. Dedicated regressions use real ConPTY. */
+export const testTerminalHostPlugin: Plugin = {
+  name: 'terminal-outside-conversation-test-scope',
+  setup(build) {
+    build.onResolve({ filter: /^\.\/terminal-host$/ }, () => ({ path: 'terminal-host', namespace: 'test-terminal-host' }))
+    build.onLoad({ filter: /.*/, namespace: 'test-terminal-host' }, () => ({ loader: 'js', contents: `
+      const unexpected = () => { throw new Error('Native terminal invoked outside dedicated terminal regression'); };
+      export const createTerminal=unexpected,getTerminal=unexpected,writeTerminal=unexpected,resizeTerminal=unexpected,
+        clearTerminal=unexpected,closeTerminal=unexpected,rebindTerminal=unexpected,disposeTerminalHosts=unexpected;
+    ` }))
+  }
+}