mock: キー追加を、選択中のキーの行の右端、または新しい行の左端に置く(T-30 単位6)

行の判定は idx-editor-feedback.md の規則(そろっている軸は座標でまとめ、
ずれている軸は隣とのつながりで1対1にたどる)を domain/rows.ts に実装し、
IDX Editor でも使えるよう列の判定も合わせて置いた。
何も選んでいないときは、コンテナの全キーの下に新しい行を作り、その左端に置く。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XsamNKrWY3obJwR746oQRq

mock/src/ui/phy/usePhyCommands.ts

@@ -16,6 +16,7 @@ import {
 } from "../../domain/phyCommands";
 import { deleteNodeCascade, listDeleteReferences } from "../../domain/deleteCascade";
 import { apply, inverse, matrix, worldTransform, type Affine } from "../../domain/geometry";
+import { newRowPosition, rowEndPosition } from "../../domain/rows";
 import { pasteLocalTransform, localBounds, treeIndex } from "./logic";
 
 type Options = {
@@ -122,13 +123,17 @@ export function usePhyCommands(options: Options) {
   function keyAdd() {
     const chosen = options.node(options.selected.value.at(-1) || "");
     const parent = chosen ? options.selectedContainer(chosen.id) : insertionParent();
+    const keys = nodesInContainer(parent).flatMap((node) =>
+      node.type === "key" ? [{ id: node.id, x: node.transform.x, y: node.transform.y, ...node.size }] : [],
+    );
+    const snap = (value: number) => Math.round(value / options.grid.value) * options.grid.value;
     const center = centerInParent(parent);
-    const x =
-      Math.round(
-        (chosen ? chosen.transform.x + (chosen.type === "key" ? chosen.size.w : 1) : center.x) /
-          options.grid.value,
-      ) * options.grid.value;
-    const y = Math.round((chosen ? chosen.transform.y : center.y) / options.grid.value) * options.grid.value;
+    const { x, y } =
+      chosen?.type === "key"
+        ? rowEndPosition(keys, chosen.id)!
+        : chosen
+          ? { x: snap(chosen.transform.x + 1), y: snap(chosen.transform.y) }
+          : (newRowPosition(keys) ?? { x: snap(center.x), y: snap(center.y) });
     let id = "";
     options.dispatch("キー追加", (project) => {
       const phy = addKeyToParent(project.phy, parent, { x, y, rotation: 0 }, { w: 1, h: 1 });