F2: EPT joined to EquipmentDataModel + server-side CEID emission

EquipmentDataModel now carries an EptStateMachine as a value member
alongside the other top-level state machines.  Server installs a
state-change handler that maps every EPT transition to a CEID emission
through the existing emit_event path:

  1100 NonScheduledTime    1103 Engineering
  1101 ScheduledDowntime   1104 Standby
  1102 UnscheduledDowntime 1105 Productive

CEIDs land in the 1100+ block to keep clear of the demo equipment.yaml
(100s/200s/400s) and E90 (900s).  Log lines include the dwell time of
the previous state so trace-level diagnostics show utilization without
extra tooling.

Application code drives transitions by calling model->ept.on_event(...);
the existing event-report machinery (subscription state, S6F11
batching, spool) gates wire emission so EPT events spool on offline
hosts like every other CEID.

Closes Tranche F — E116 Equipment Performance Tracking end-to-end.

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

include/secsgem/gem/e116_constants.hpp

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <cstdint>
+
+// E116 §6 standard collection-event identifiers, one per top-level
+// state.  Equipment fires the matching CEID on transition into that
+// state; hosts subscribe via the existing S2F33 / S2F35 / S2F37 flow.
+namespace secsgem::gem::e116 {
+
+inline constexpr uint32_t kCeidNonScheduledTime    = 1100;
+inline constexpr uint32_t kCeidScheduledDowntime   = 1101;
+inline constexpr uint32_t kCeidUnscheduledDowntime = 1102;
+inline constexpr uint32_t kCeidEngineering         = 1103;
+inline constexpr uint32_t kCeidStandby             = 1104;
+inline constexpr uint32_t kCeidProductive          = 1105;
+
+}  // namespace secsgem::gem::e116