Fix Story 2.3 code review findings: remove duplicate ParticipantCard.js, fix lint in ScryingPoolStrip.js

- Delete src/ui/shared/ParticipantCard.js (duplicate of boardUtils.js with conflicting implementations)
- Delete tests/unit/ui/shared/ParticipantCard.test.js (tests for deleted file)
- Add directorsBoard to global declarations in ScryingPoolStrip.js to fix lint errors

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

src/utils/boardUtils.js

@@ -0,0 +1,51 @@
+// @ts-nocheck
+/**
+ * boardUtils.js
+ * Shared utility functions for participant board operations.
+ * Can be imported by both src/ui/ and other modules without violating import boundaries.
+ */
+
+/**
+ * Resolves the target state for a visibility toggle action.
+ * active → hidden, hidden → active, ghost → ghost (no toggle)
+ * @param {string} currentState
+ * @returns {string} Target state
+ */
+export function resolveToggleTarget(currentState) {
+  if (currentState === 'ghost') return 'ghost';
+  if (currentState === 'hidden') return 'active';
+  return 'hidden';
+}
+
+/**
+ * Builds context for a single participant in the Director's Board.
+ * @param {object} stateStore
+ * @param {string} userId
+ * @returns {object} Participant context
+ */
+export function buildSimpleParticipantContext(stateStore, userId) {
+  const state = stateStore.getState(userId);
+  return {
+    userId,
+    state: state ?? 'active',
+    isGhost: state === 'ghost',
+  };
+}
+
+/**
+ * Builds context for the Director's Board grid.
+ * @param {object} stateStore
+ * @param {object} controller
+ * @param {object} adapter
+ * @returns {object} Board context
+ */
+export function buildBoardContext(stateStore, controller, adapter) {
+  try {
+    const users = adapter.users.all?.() ?? [];
+    const participants = users.map(u => buildSimpleParticipantContext(stateStore, u.id ?? u));
+    return { participants, isEmpty: participants.length === 0 };
+  } catch (err) {
+    console.error('[ScryingPool] buildBoardContext failed:', err);
+    return { participants: [], isEmpty: true };
+  }
+}