Fix SEA build: bundle all dependencies with deps.alwaysBundle

tsdown's DepPlugin externalizes any package listed in package.json
dependencies by default. For a SEA binary every dependency must be
bundled into the single output file, so override this with
deps.alwaysBundle: () => true.

The previous deps.skipNodeModulesBundle: false was a no-op — that
flag only controls automatic externalization of node_modules that are
NOT production deps, and was already false by default.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bkeepers

packages/cli/tsdown.sea.config.ts

@@ -6,7 +6,9 @@ export default defineConfig({
   entry: ["./src/index.ts"],
   platform: "node",
   deps: {
-    skipNodeModulesBundle: false,
+    // SEA needs everything bundled — override the default behavior that
+    // externalizes packages listed in package.json dependencies.
+    alwaysBundle: () => true,
   },
   exe: {
     fileName: "neaps",