Wire command zone menu, harden counter command handling, and expand tests

- Connect aMoveToCommandZone to cmMoveToCommandZone; the menu item was
    added, shown, and shortcut-bound but never wired, so it did nothing
  - Extract evaluateModifyCounter() and route cmdIncCounter/cmdSetCounter
    through it, replacing isCommandZoneCounterBlocked; reject inc/set on
    an inactive tax counter so a hidden counter cannot accumulate value
  - Reject reserved tax counter names in cmdCreateCounter to prevent a
    client from spoofing a system tax counter via a user-created counter
  - Route AbstractCounter::valueChanged through the virtual setValue() so
    CommanderTaxCounter clamps and refreshes its tooltip on value changes
  - Deduplicate actPlayAndIncreaseTax/actPlayAndIncreasePartnerTax into a
    single playAndIncreaseTax(counterId) helper
  - Move MINIMUM_STACKING_HEIGHT from CommandZone to the PlayerGraphicsItem
    layout code, its only consumer
  - Remove unused AbstractCounter forward declaration from player_logic.h
  - Add EvaluateModifyCounter tests and PartnerTax cases for
    evaluateSetCounterActive
  - Pin the FirstUserId floor in new_counter_id_test using ids 3 and 5 so
    a naive "highest id + 1" regression fails the test

cockatrice/src/game_graphics/board/abstract_counter.cpp

@@ -28,10 +28,9 @@ AbstractCounter::AbstractCounter(CounterState *state,
 {
     setAcceptHoverEvents(true);
 
-    connect(state, &CounterState::valueChanged, this, [this](int, int newValue) {
-        value = newValue;
-        update();
-    });
+    // Route through the (possibly overridden) virtual setValue so subclasses such as
+    // CommanderTaxCounter can clamp and refresh their tooltip on every value change.
+    connect(state, &CounterState::valueChanged, this, [this](int, int newValue) { setValue(newValue); });
 
     connect(state, &CounterState::activeChanged, this, [this](bool newActive) {
         setActive(newActive);