Feature: Plan Lifecycle Service coverage boost
  As a developer
  I want to exercise uncovered branches in PlanLifecycleService
  So that code coverage improves for the specific gaps identified

  Background:
    Given I have a fresh plan lifecycle service for coverage boost

  # ---------------------------------------------------------------
  # Line 284: get_action_by_name linear scan fallback
  # Branch 283:284 — the dict key doesn't match but the action's
  # namespaced_name string representation does.
  # ---------------------------------------------------------------

  Scenario: get_action_by_name normalises case so mixed-case input finds lowercase-stored action
    Given an action stored under its normalised lowercase key
    When I look up the action with mixed-case input via get_action_by_name
    Then the action should be found via case-insensitive lookup

  # ---------------------------------------------------------------
  # Line 420: use_action appends PlanInvariant from action.invariants
  # Branch 419:420 — the loop body over action.invariants
  # ---------------------------------------------------------------

  Scenario: use_action copies action invariants as PlanInvariants onto the new plan
    Given an action with invariants "no-breaking-changes" and "preserve-api-compat"
    When I use that action to create a plan
    Then the plan should contain 2 action-sourced invariants
    And the invariant texts should include "no-breaking-changes"
    And the invariant texts should include "preserve-api-compat"

  # ---------------------------------------------------------------
  # Line 643: execute_plan raises InvalidPhaseTransitionError
  # Branch 642:643 — can_transition returns False
  # ---------------------------------------------------------------

  Scenario: execute_plan raises InvalidPhaseTransitionError when plan is in Execute phase
    Given a plan that is already in execute phase
    When I try to execute the plan from execute phase
    Then an InvalidPhaseTransitionError should be raised for the coverage boost

  Scenario: execute_plan raises InvalidPhaseTransitionError when plan is in Apply phase
    Given a plan that is already in apply phase
    When I try to execute the plan from apply phase
    Then an InvalidPhaseTransitionError should be raised for the coverage boost

  # ---------------------------------------------------------------
  # Lines 829-846: constrain_apply method — happy path and wrong phase
  # Branches 831:832,836
  # ---------------------------------------------------------------

  Scenario: constrain_apply marks an Apply-phase plan as constrained
    Given a plan in apply phase with processing state for coverage boost
    When I constrain the apply with reason "invariant violated" for coverage boost
    Then the plan processing state should be "constrained" for coverage boost
    And the plan error message should be "invariant violated" for coverage boost

  Scenario: constrain_apply raises PlanError when plan is not in Apply phase
    Given a plan in strategize phase for coverage boost
    When I try to constrain the apply with reason "should fail"
    Then a PlanError should be raised for coverage boost

  # ---------------------------------------------------------------
  # Line 959: auto_progress final return — plan doesn't match either
  # auto-progress condition.
  # Branch 948:959 — the else/fallback in auto_progress
  # ---------------------------------------------------------------

  Scenario: auto_progress returns plan unchanged when neither auto-progress condition matches
    Given a plan in strategize queued state with full automation for coverage boost
    When I call auto_progress on the plan for coverage boost
    Then the plan should be returned unchanged in strategize queued state