100%/A: S5F7/F8 list enabled alarms

Closes the small remaining hole in Alarm Management.  S5F7 is
header-only; S5F8 has the same wire shape as S5F6 (vector of
<L,3 <B ALCD> <U4 ALID> <A ALTX>>) but only includes alarms whose
enabled flag is set.  Codegen handles both as a list_of with
struct_name=AlarmListing; server pre-computes the per-row ALCD from
(severity_category, active state) before passing the rows in.

COMPLIANCE.md: Alarm Management Additional capability flips ✅.

Tests: 78 cases / 454 assertions.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/secs_server.cpp

@@ -335,6 +335,18 @@ int main(int argc, char** argv) {
     logfn(std::string("S5F3 -> S5F4 ACKC5=") + std::to_string(static_cast<int>(ack)));
     return gem::s5f4_enable_alarm_ack(ack);
   });
+  router.on(5, 7, [model, logfn](const s2::Message&) {
+    std::vector<gem::AlarmListing> rows;
+    for (const auto& a : model->alarms.all()) {
+      if (!model->alarms.enabled(a.id)) continue;
+      const uint8_t alcd = (a.severity_category & 0x7F) |
+                           static_cast<uint8_t>(model->alarms.active(a.id) ? 0x80 : 0x00);
+      rows.push_back({alcd, a.id, a.text});
+    }
+    logfn("S5F7 -> S5F8 (" + std::to_string(rows.size()) + " enabled)");
+    return gem::s5f8_list_enabled_alarms_data(rows);
+  });
+
   router.on(5, 5, [model, logfn](const s2::Message& msg) {
     auto ids = gem::parse_u4_list_body(msg);
     std::vector<gem::Alarm> alarms;