D1: E87 carrier and load-port state machines

Per-carrier triple FSM: CIDS (id verification), CSMS (slot-map), CAS
(access).  Per-port triple FSM: LPTS (transfer), LRS (reservation), LAS
(association).  Wire-byte enum values pinned via static_assert to match
E87-0716 §10.3.

CarrierStateMachine combines the three carrier-side FSMs because they
are independent but always observed together; same for LoadPortState-
Machine.  Generic CarrierTransitionTable<State, Event> template is
reused across all six tables — same row shape as the PJ/CJ/Exception
tables that already exist.

Default tables cover the spec's documented transitions:
  CIDS: NotConfirmed <-> Confirmed/Mismatched/Unknown, Cancel returns
        to NotConfirmed from any state, Bind force-confirms.
  CSMS: NotRead -> Read -> {Mismatched, Reset}.
  CAS:  NotAccessed -> InAccess -> Complete (terminal).
  LPTS: OutOfService <-> InService <-> Loading/Unloading.
  LRS / LAS: simple boolean toggle pairs.

15 test cases assert the happy-path lifecycles, cross-state cancels,
and that change handlers fire only on real transitions (Read in
NotConfirmed is a no-op, not a handler call).

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

CMakeLists.txt

@@ -54,6 +54,8 @@ add_library(secsgem
   src/gem/process_job_state.cpp
   src/gem/control_job_state.cpp
   src/gem/exception_state.cpp
+  src/gem/carrier_state.cpp
+  src/gem/load_port_state.cpp
   src/gem/host_handler.cpp
   src/config/loader.cpp
   src/endpoint.cpp
@@ -98,6 +100,7 @@ add_executable(secsgem_tests
   tests/test_process_jobs.cpp
   tests/test_control_jobs.cpp
   tests/test_exceptions.cpp
+  tests/test_carrier_state.cpp
 )
 target_link_libraries(secsgem_tests PRIVATE secsgem doctest::doctest)
 target_compile_definitions(secsgem_tests PRIVATE