feat(battle-engine-port): M2 step 1 — SingleBattleMgr constructs headless

First green of the M2 go/no-go probe: `new SingleBattleMgr(StandardBattleMgr-
ContentsCreator)` now builds the two-player pair fully headless against the shim,
no Unity runtime. Verdict: headless construction is feasible; every blocker was a
mechanical no-op shim fill or data seam, not a Unity/logic wall.

Shim fills (authored):
- GameMgr: lazy non-null DataMgr/PrefabMgr/InputMgr/SoundMgr/BattleControl.
- GameObject: lazy cached component model so GetComponent<T>/AddComponent<T> return
  non-null no-op instances for Component-derived T (F1: unguarded view touches).
- Resources.Load(string): cached non-null GameObject so the prefab->Instantiate->
  GetComponent chain (UnityEventAgent) yields a real object.
- ClassBattleCardViewBase: re-attach dropped IClassBattleCardView (no-op members);
  ClassBattleCardBase.Setup casts the created view to it.

Engine copy (DP1/DP3 mis-cut fix):
- CardIconControl.cs copied verbatim (manifested) + generated null-stub deleted.
  SplitAndCompleteIconStr is pure string logic on the resolution path that M1 had
  wrongly stubbed as "View" -> null deref in SkillCreator.CreateBuildInfo.

Test harness (SVSim.BattleEngine.Tests, authored fixture):
- HeadlessContentsCreator/HeadlessPhaseCreator: deterministic replica of the solo
  practice init (StandardBattleMgrContentsCreator + SingleBattlePhaseCreator) with
  no-op recovery/replay managers.
- HeadlessCardMaster: reflects the loader cards.json dump into CardMaster.
- HeadlessMasterData: minimal Data.Master (class-character list, empty collections)
  + Data.Load + player/enemy chara ids.
- ConstructionProbeTests.SingleBattleMgr_constructs_headless — GREEN.

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

SVSim.BattleEngine/COPIED.manifest.tsv

@@ -3308,3 +3308,4 @@ WrapVariableContentsScrollBarSize.cs	WrapVariableContentsScrollBarSize.cs	05c94e
 YuwanField.cs	YuwanField.cs	1368d0b2755edbae36ce4dcabd69d8d2f6ce854765ea46621199ef20d407d13a	0
 iTween.cs	iTween.cs	8da77cd885d8fb1e8727e91681ab5ac00a889d0fcc9b973a4162f15a0b642a54	0
 llField.cs	llField.cs	a0e0eaed3f22a8c4ce47f82fa80346e3b99e3ac0a6765e1ad4ade3a87c1b0189	0
+Wizard.Battle.View/CardIconControl.cs	Wizard.Battle.View/CardIconControl.cs	affd5a289a04bc9f446f3e892403dd9cd560ee557de1e5cd743dcb031dab280c	0