H1: ModuleStateMachine + ModuleStore (E157 §6)

Per-module process-tracking state machine.  An E157 instance models a
single recipe step at a single module, with the canonical lifecycle:

  NotExecuting -> GeneralExecuting (StartGeneral)
                -> StepExecuting   (StartStep)
                -> StepCompleted   (CompleteStep)

Plus universal escape hatches: Reset returns any state to
NotExecuting; Abort terminates from any state to StepCompleted.

ModuleStore wraps the FSM with the now-standard pattern:
  - non-movable (this-capture lambdas)
  - per-module bind() carries current_substid + recipe_step
  - fire(module_id, event) delegates to the FSM
  - set_state_change_handler observes every transition with module_id

Joins EquipmentDataModel.  5 test cases cover happy path, Reset from
each interior state, Abort, store-level create dedup + bind, and the
multi-module change handler keying.

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

CMakeLists.txt

@@ -59,6 +59,7 @@ add_library(secsgem
   src/gem/substrate_state.cpp
   src/gem/ept_state.cpp
   src/gem/cem_objects.cpp
+  src/gem/module_state.cpp
   src/gem/host_handler.cpp
   src/config/loader.cpp
   src/endpoint.cpp
@@ -108,6 +109,7 @@ add_executable(secsgem_tests
   tests/test_substrates.cpp
   tests/test_ept.cpp
   tests/test_cem_objects.cpp
+  tests/test_modules.cpp
 )
 target_link_libraries(secsgem_tests PRIVATE secsgem doctest::doctest)
 target_compile_definitions(secsgem_tests PRIVATE