✅ Feat(Contract): v5.2 BP 编辑命令模式 — 新增 BpEditAction record 族 + 移除废弃 IBlueprintConverter

- 新增 BpEditAction 抽象 record + 12 个具体编辑动作（AddNodeInBlock/DeleteNode/MoveNodeToBlock/SetNodeArgument/ConnectData/Disconnect/SetControlFlowArm/AddBlock/RenameBlock/DeleteBlock/MoveNodePosition）
- 纯数据 record，无 CFG/Workflow 依赖，供 Dashboard 描述用户编辑、IBpEditApplier 翻译为 IR 变更
- 移除 IBlueprintConverter.cs（v5.1 已废弃，BS↔BP 转换改走 CFG 真相源 + ICfgBsRenderer/ICfgBpRenderer）

Author: StardustSeemsInk

KitX Core Contracts/KitX.Core.Contract/Workflow/BpEditAction.cs

@@ -0,0 +1,44 @@
+// v5.2 BP editing action hierarchy (command pattern).
+// Pure data records — no dependency on CFG or Workflow types.
+// Dashboard creates these to describe a user edit; IBpEditApplier translates them to CFG mutations.
+
+namespace KitX.Core.Contract.Workflow;
+
+public abstract record BpEditAction;
+
+// ── Node-level ──
+
+/// <param name="Position">Insertion index within the block (null = append).</param>
+public record AddNodeInBlock(string BlockName, string BpNodeKind, int? Position = null) : BpEditAction;
+
+/// <param name="NodeId">The BP node id to delete.</param>
+public record DeleteNode(string NodeId) : BpEditAction;
+
+/// <param name="TargetBlock">Destination block.</param>
+/// <param name="Position">Insertion index within the target block (null = append).</param>
+public record MoveNodeToBlock(string NodeId, string TargetBlock, int? Position = null) : BpEditAction;
+
+/// <param name="ArgIndex">Zero-based argument index.</param>
+public record SetNodeArgument(string NodeId, int ArgIndex, string Value) : BpEditAction;
+
+// ── Connection-level (data flow) ──
+
+public record ConnectData(string SourceNodeId, string SourcePin, string TargetNodeId, string TargetPin, string? PubVarName = null) : BpEditAction;
+
+public record Disconnect(string ConnectionId) : BpEditAction;
+
+// ── Control flow (Exec arms) ──
+
+public record SetControlFlowArm(string NodeId, string ArmPinName, string TargetBlockName) : BpEditAction;
+
+// ── Block-level ──
+
+public record AddBlock(string BlockName) : BpEditAction;
+
+public record RenameBlock(string OldName, string NewName) : BpEditAction;
+
+public record DeleteBlock(string BlockName) : BpEditAction;
+
+// ── Position (G5) ──
+
+public record MoveNodePosition(string NodeId, double X, double Y) : BpEditAction;