feat(privacy-host): add signed native calendar contacts and reminders host

Add the owner-only AF_UNIX Reyna CLI privacy host, strict signed-app installation, and typed native routing for Calendar, Contacts, and Reminders.\n\nAdd bounded system-status paths and config-only direct local-service wrappers. Preserve MacMiniMCP pending explicit cutover approval.\n\nApple Notes is intentionally deferred: no native Notes operations, Apple Events declaration, or Automation helper are included; legacy Notes handling remains untouched.

native/ReynaCLIHost/Sources/CSignalSupport/CSignalSupport.c

@@ -0,0 +1,43 @@
+#include "CSignalSupport.h"
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <stddef.h>
+
+static char g_socket_path[104 * 4];
+static volatile sig_atomic_t g_has_path = 0;
+
+void reyna_store_socket_path(const char *path) {
+    if (!path) {
+        g_socket_path[0] = '\0';
+        g_has_path = 0;
+        return;
+    }
+    strncpy(g_socket_path, path, sizeof(g_socket_path)-1);
+    g_socket_path[sizeof(g_socket_path)-1] = '\0';
+    g_has_path = 1;
+}
+
+void reyna_cleanup_socket_sync(void) {
+    if (!g_has_path) return;
+    if (g_socket_path[0] == '\0') return;
+    unlink(g_socket_path);
+}
+
+static void reyna_signal_handler(int sig) {
+    (void)sig;
+    reyna_cleanup_socket_sync();
+    _exit(0);
+}
+
+void reyna_install_signal_handlers(void) {
+    struct sigaction sa;
+    memset(&sa, 0, sizeof(sa));
+    sa.sa_handler = reyna_signal_handler;
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+    sigaction(SIGTERM, &sa, NULL);
+    sigaction(SIGINT, &sa, NULL);
+    sigaction(SIGHUP, &sa, NULL);
+    signal(SIGPIPE, SIG_IGN);
+}