Card-Crack: Cardputer ESP32-S3 home-lab recon toolkit

Manual-trigger firmware toolkit for pentesting owned devices:
- Pin Scan: UART/JTAG/SWD detection (baud est + IDCODE reads)
- V-Sense: target voltage probe w/ logic-family guess
- UART Sniff: passive capture + manual-only frame replay
- USB Enum: ESP32-S3 host, read-only descriptor fingerprinting
- DefCred: single-host factory-default login check, rate-limited

Modular shell (core/ + modules/), PlatformIO build, hardware/safety docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AAhMHMRAQLQ9hSbBECKNfn

src/core/shell.h

@@ -0,0 +1,20 @@
+#pragma once
+#include "module.h"
+
+// The shell: owns the module list, the main menu, and event routing.
+// Backtick (`) always returns to the menu from inside a module.
+class Shell {
+public:
+  void begin();
+  void loop();
+private:
+  static constexpr int MAX = 12;
+  Module* mods[MAX]; int nmods = 0;
+  int sel = 0;              // menu cursor
+  int active = -1;          // -1 == in menu
+  uint32_t lastTick = 0;
+  void add(Module* m) { if (nmods < MAX) mods[nmods++] = m; }
+  void drawMenu();
+  void enter(int i);
+  void back();
+};