fix(lockscreen): correct main.cpp injection anchor and early-return guard

plugins/lockscreen/LockscreenPlugin.cpp

@@ -0,0 +1,40 @@
+#include "LockscreenPlugin.h"
+
+namespace LockscreenPlugin {
+
+const char* modeName(LockscreenMode mode) {
+    switch (mode) {
+        case LockscreenMode::ENABLED: return "Enabled";
+        default:                      return "Disabled";
+    }
+}
+
+bool shouldLock(LockscreenMode mode) {
+    return mode == LockscreenMode::ENABLED;
+}
+
+bool shouldLockOnWake(LockscreenMode mode) {
+    return shouldLock(mode);
+}
+
+bool shouldLockOnPower(LockscreenMode mode) {
+    return shouldLock(mode);
+}
+
+void hashPin(const char* pin, char outHash[9]) {
+    uint32_t hash = 5381;
+    for (const char* p = pin; *p; p++) {
+        hash = ((hash << 5) + hash) ^ static_cast<uint8_t>(*p);
+    }
+    hash ^= 0xA3F1C2B4u;
+    snprintf(outHash, 9, "%08X", hash);
+}
+
+bool checkPin(const char* pin, const char* storedHash) {
+    if (!pin || !storedHash || storedHash[0] == '\0') return false;
+    char computed[9];
+    hashPin(pin, computed);
+    return strncmp(computed, storedHash, 9) == 0;
+}
+
+}