Add experimental RTX 5090 (GDDR7) memory temperature support

Reads the per-module GDDR7 DRAM sensors (FBPA DQR) directly and reports
the hotspot by default; --per-module lists each of the 8 modules.
Adds a per-device decode so the existing GDDR6/6X path is unchanged.

app/src/app.c

@@ -2,6 +2,7 @@
 #include "gddr6.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <signal.h>
 
 void register_signal_handlers(void)
@@ -18,6 +19,21 @@ void register_signal_handlers(void)
 
 int main(int argc, char **argv)
 {
+    int per_module = 0;
+    for (int i = 1; i < argc; i++)
+    {
+        if (strcmp(argv[i], "--per-module") == 0)
+            per_module = 1;
+        else if (strcmp(argv[i], "--help") == 0 || strcmp(argv[i], "-h") == 0)
+        {
+            printf("Usage: %s [--per-module]\n"
+                   "  (default)      show VRAM temperature (Blackwell: hottest module)\n"
+                   "  --per-module   show each GDDR7 module separately (Blackwell only)\n",
+                   argv[0]);
+            return 0;
+        }
+    }
+
     register_signal_handlers();
     gddr6_init();
     int num_devs = gddr6_detect_compatible_gpus();
@@ -29,7 +45,7 @@ int main(int argc, char **argv)
     }
 
     gddr6_memory_map();
-    gddr6_monitor_temperatures();
+    gddr6_monitor_temperatures(per_module);
 
     return 0;
 }