scaffold: 4 new module dirs (sudo_samedit, sequoia, sudoedit_editor, vmwgfx)

Stubs returning PRECOND_FAIL. Parallel agents fill in real detect/exploit.

modules/sequoia_cve_2021_33909/skeletonkey_modules.c

@@ -0,0 +1,20 @@
+/* sequoia_cve_2021_33909 — STUB pending agent implementation. */
+#include "skeletonkey_modules.h"
+#include "../../core/registry.h"
+
+static skeletonkey_result_t sequoia_detect(const struct skeletonkey_ctx *ctx)
+{ (void)ctx; return SKELETONKEY_PRECOND_FAIL; }
+
+const struct skeletonkey_module sequoia_module = {
+    .name = "sequoia",
+    .cve = "CVE-2021-33909",
+    .summary = "seq_file size_t overflow → kernel stack write (Qualys Sequoia) — stub pending implementation",
+    .family = "filesystem",
+    .kernel_range = "K < 5.13.4 / 5.10.52 / 5.4.134",
+    .detect = sequoia_detect,
+    .exploit = NULL, .mitigate = NULL, .cleanup = NULL,
+    .detect_auditd = NULL, .detect_sigma = NULL,
+    .detect_yara = NULL,   .detect_falco = NULL,
+};
+
+void skeletonkey_register_sequoia(void) { skeletonkey_register(&sequoia_module); }