fix(cli): keep source launch output clean

scripts/run-source-dsh.ts

@@ -0,0 +1,48 @@
+/**
+ * Source-checkout launcher. Successful build output stays out of CLI stdout;
+ * build failures report their captured diagnostics on stderr before exiting.
+ */
+import process from 'node:process'
+import { fileURLToPath } from 'node:url'
+
+import { execa } from 'execa'
+
+const repoRoot = fileURLToPath(new URL('..', import.meta.url))
+const sourceBin = fileURLToPath(new URL('../apps/cli/src/bin.ts', import.meta.url))
+
+function completeFrom(result: { readonly exitCode?: number; readonly signal?: string }): void {
+  if (result.signal !== undefined) {
+    process.kill(process.pid, result.signal)
+    return
+  }
+  process.exitCode = result.exitCode ?? 1
+}
+
+function reportBuildFailure(result: {
+  readonly all: string | undefined
+  readonly shortMessage: string | undefined
+}): void {
+  const diagnostic = result.all === undefined || result.all.length === 0
+    ? result.shortMessage ?? 'Source build failed without diagnostics.'
+    : result.all
+  process.stderr.write(diagnostic.endsWith('\n') ? diagnostic : `${diagnostic}\n`)
+}
+
+const build = await execa('pnpm', ['run', 'build'], {
+  all: true,
+  cwd: repoRoot,
+  reject: false,
+  stripFinalNewline: false,
+})
+if (build.failed) {
+  reportBuildFailure(build)
+  completeFrom(build)
+} else {
+  const cli = await execa(process.execPath, ['--import', 'tsx/esm', sourceBin, ...process.argv.slice(2)], {
+    cwd: repoRoot,
+    env: { ...process.env, NODE_USE_ENV_PROXY: '1' },
+    reject: false,
+    stdio: 'inherit',
+  })
+  completeFrom(cli)
+}