feat: add eintrtarget and envprint

user/false.c

@@ -0,0 +1,15 @@
+#include "ulib.h"
+
+/*
+ * Real POSIX false(1): does nothing, always exits 1. Exists purely so
+ * shell.c's new `&&`/`||` conditional chaining (execute()/executeSingle,
+ * shellSplitAndOr in shell.h) has a genuinely SPAWNED process (real
+ * fork-less spawn + real userExit, not just a builtin's own int return
+ * like doExport/changeDir) whose nonzero exit status drives a real `&&`
+ * skip followed by a real `||` fallback -- kmain.c's andOrDriverThread
+ * types `false && echo x || echo ao2` at the live shell to prove it.
+ */
+int main(void)
+{
+    return 1;
+}