C1: ExceptionStateMachine FSM + ExceptionStore

Per-EXID exception lifecycle for E5 §9.  States mirror the wire flow:

  Posted          equipment sent S5F9, awaiting host or autonomous clear
  Recovering      host's S5F13 accepted; equipment running recovery
  RecoverFailed   S5F15 reported a failed result; host may retry
  Cleared         terminal — store removes the row

Events:
  Created          synthetic NoState->Posted observer signal
  Recover          host's S5F13 (Posted/RecoverFailed -> Recovering)
  RecoveryComplete equipment internal (Recovering -> Cleared)
  RecoveryFailed   equipment internal (Recovering -> RecoverFailed)
  RecoveryAbort    host's S5F17 (Recovering -> Posted)
  Clear            equipment internal (Posted/RecoverFailed -> Cleared)

ExceptionStore mirrors ProcessJobStore: per-EXID FSMs heap-allocated via
unique_ptr, non-movable to keep `this`-captures safe, synthetic Created
fires after the row lands so observers can decide whether to emit S5F9
out of band.  on_recover validates EXRECVRA against the candidates the
post advertised.

The store joins EquipmentDataModel alongside process_jobs / control_jobs.
S5F9-F18 server-side dispatch lands in C2.

Tests (12 cases) cover FSM transitions including retry, abort, and
autonomous clear, plus store-level duplicate-rejection, EXRECVRA
validation, and Cleared-removes-the-row semantics.

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

include/secsgem/gem/data_model.hpp

@@ -5,6 +5,7 @@
 #include "secsgem/gem/store/control_jobs.hpp"
 #include "secsgem/gem/store/equipment_constants.hpp"
 #include "secsgem/gem/store/event_reports.hpp"
+#include "secsgem/gem/store/exceptions.hpp"
 #include "secsgem/gem/store/host_commands.hpp"
 #include "secsgem/gem/store/limits.hpp"
 #include "secsgem/gem/store/process_jobs.hpp"
@@ -34,6 +35,7 @@ struct EquipmentDataModel {
   TraceStore                traces;
   ProcessJobStore           process_jobs;
   ControlJobStore           control_jobs;
+  ExceptionStore            exceptions;
 
   // Convenience: VID -> value lookup spanning SVIDs and DVIDs.
   std::optional<s2::Item> vid_value(uint32_t vid) const {