feat: add SYS_GETCAPS syscall to retrieve process capabilities

kernel/src/Api/Process.hpp

@@ -140,6 +140,16 @@ namespace montauk::abi {
         return childPid;
     }
 
+    // The calling process's own capability masks.
+    static int Sys_GetCaps(SpawnCapabilities* out) {
+        auto* proc = Sched::GetCurrentProcessPtr();
+        if (proc == nullptr || out == nullptr) return -1;
+        out->permitted = proc->permittedCaps;
+        out->effective = proc->effectiveCaps;
+        out->delegable = proc->delegableCaps;
+        return 0;
+    }
+
     // Copy the absolute path this process was spawned from (argv[0]).
     static int Sys_GetExecPath(char* buf, uint64_t maxLen) {
         auto* proc = Sched::GetCurrentProcessPtr();