feat(battle-engine-port): M2 COMPLETE — vanilla follower resolves headless (go/no-go = GO)

First green: a zero-skill vanilla follower (100011010, neutral 1/2) resolves to
correct authoritative state HEADLESS via IsForecast/IsRecovery + ActionProcessor.
PlayCard (DP4), no Unity runtime. §5 oracle passes (PP-cost; hand->in-play;
atk/health == CardCSVData base; opponent unchanged; no exception). VERDICT: the
port approach is validated through the resolution path, not just M1's compile path.

VanillaFollowerOracleTests.Vanilla_follower_resolves_to_correct_state — GREEN.
HeadlessCardMaster now loads the follower's real id from cards.json.

Resolution-path shim/engine gaps closed (all mechanical no-op fills or data seams,
never a Unity/logic wall):
- M1 mis-cut copies (DP1/DP3 — pure no-op logic wrongly stubbed to null):
  Engine/Wizard.Battle.View.Vfx/NullCardVfxCreator.cs (its GetInstance() singleton
  was nulled) + its dep NotEmptyNullVfx.cs. Deleted the generated NullCardVfxCreator
  stub + its _IfaceImpl block; both manifested, check_drift clean.
- _IfaceImpl explicit-impl shadow: interface-typed view/mgr calls dispatch to the
  explicit impls (which returned default!), shadowing public stubs. Fixed
  IBattlePlayerView.GetSideLogControl (SkillProcessor side-log tail) to return a
  non-null no-op. KEY M3+ learning: fix _IfaceImpl.g.cs for interface-typed NREs.

(GameMgr/component-model/Resources/IClassBattleCardView shim fills + CardIconControl
copy + the SVSim.BattleEngine.Tests project landed in the prior commit 2b50657.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleEngine.Tests/HeadlessFixture.cs

@@ -11,6 +11,9 @@ namespace SVSim.BattleEngine.Tests
     // is populated from /load/index at login; here we author the minimum the resolution path reads.
     public static class HeadlessEngineEnv
     {
+        // Simplest zero-skill vanilla follower in cards.json: neutral (clan 0), cost 1, 1/2, no skill.
+        public const int FollowerId = 100011010;
+
         private static bool _done;
 
         public static void EnsureInitialized()
@@ -19,10 +22,15 @@ namespace SVSim.BattleEngine.Tests
             // Wizard.Data.Load: static /load/index snapshot. The ctor's CreateBackgroundId reads
             // Data.Load.data._userTutorial (LoadDetail self-inits _userTutorial). Suppress VFX too.
             Wizard.Data.Load = new Load { data = new LoadDetail() };
+            // CardParameter(CardCSVData) reads Data.Crossover.RestrictedCard for deck-limit calc;
+            // an empty Crossover returns the default count (no restriction). Private setter -> reflect.
+            typeof(Wizard.Data).GetProperty("Crossover",
+                System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public)
+                .SetValue(null, new Wizard.Crossover());
             BattleManagerBase.IsForecast = true;
             // CardMaster must be non-null before construction (the leader/class card looks up id 0).
-            // Empty load suffices for construction; the oracle reloads with the follower's real id.
-            HeadlessCardMaster.Load();
+            // Load the M2 vanilla follower so the oracle can create + look up its real stats.
+            HeadlessCardMaster.Load(FollowerId);
             // Master reference data (class-character list) for leader/class card resolution.
             HeadlessMasterData.Install();
             // Player/enemy leaders (chara ids must map to a ClassCharacterMasterData in Master).