mock: 長押しの処理を usePhyLongPress に切り出す(T-30 単位7a)

候補・巡回のタイマー・表示ラベルを usePhyLongPress に移し、
usePhyCanvasPointer はドラッグ・クリックとの接続だけを持つ。挙動は変えない。
7b で2方式を入れる土台にする。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BKxNtqjjPyttUfT1TgC7Qt

mock/src/ui/phy/usePhyLongPress.ts

@@ -0,0 +1,88 @@
+import { ref } from "vue";
+
+type Options = {
+  parentLabel: (id: string | null) => string;
+  pressTargets: (id: string) => string[];
+};
+
+export type LongPressPick = { id: string; shift: boolean };
+
+// キーの長押しで、キー → 親 → … の順に選択先を巡回する。
+// ポインタの扱い(ドラッグ・クリック)は呼び出し側が持ち、ここは候補と表示だけを持つ。
+export function usePhyLongPress(options: Options) {
+  const label = ref("");
+  const labelPos = ref({ x: 0, y: 0 });
+  const candidates = ref<string[]>([]);
+  const index = ref(0);
+  let timer: number | undefined;
+  let cycle: number | undefined;
+  let shift = false;
+  let activated = false;
+
+  function reset() {
+    activated = false;
+  }
+
+  function start(event: PointerEvent, keyId: string) {
+    candidates.value = options.pressTargets(keyId);
+    index.value = 0;
+    shift = event.shiftKey;
+    timer = window.setTimeout(() => {
+      if (candidates.value.length <= 1) return;
+      activated = true;
+      index.value = 1;
+      labelPos.value = { x: event.clientX, y: event.clientY };
+      label.value = `${options.parentLabel(candidates.value[1]!)} 2/${candidates.value.length}`;
+      cycle = window.setInterval(() => {
+        index.value = (index.value + 1) % candidates.value.length;
+        const id = candidates.value[index.value]!;
+        const name = index.value === 0 ? "キー" : options.parentLabel(id);
+        label.value = `${name} ${index.value + 1}/${candidates.value.length}`;
+      }, 450);
+    }, 500);
+  }
+
+  function cycling() {
+    return label.value !== "";
+  }
+
+  function cancelPending() {
+    if (timer && !label.value) {
+      window.clearTimeout(timer);
+      timer = undefined;
+    }
+  }
+
+  function take(): LongPressPick {
+    const id = candidates.value[index.value]!;
+    if (cycle) window.clearInterval(cycle);
+    label.value = "";
+    return { id, shift };
+  }
+
+  function finish(): LongPressPick | null {
+    if (timer) window.clearTimeout(timer);
+    if (cycle) window.clearInterval(cycle);
+    const id = label.value ? candidates.value[index.value] : undefined;
+    label.value = "";
+    return id ? { id, shift } : null;
+  }
+
+  function wasActivated() {
+    return activated;
+  }
+
+  return {
+    label,
+    labelPos,
+    candidates,
+    index,
+    reset,
+    start,
+    cycling,
+    cancelPending,
+    take,
+    finish,
+    wasActivated,
+  };
+}