add header rescan button to apply officer-items changes without restart

New POST /api/rescan re-runs the boot item setup (ensureItemDirs +
ensureToolLoader) and returns live item counts; the header button calls it
and invalidates the item query caches so the UI refetches from disk.

Also fix ensure-tool-loader to write into OFFICER_ITEMS_DIR/extensions (the
runtime read path) instead of the now-unread DATA_PATH/extensions.

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

src/servers/api/items/rescan.ts

@@ -0,0 +1,39 @@
+import { readdirSync, existsSync } from 'node:fs';
+import { join } from 'node:path';
+import { createRouter } from '../../create-router';
+import { ITEM_TYPES, itemsDir, ensureItemDirs, type ItemType } from '../../data-path';
+import { ensureToolLoader } from '../../ensure-tool-loader';
+
+// Re-applies the boot-time item setup so changes under OFFICER_ITEMS_DIR take effect without a
+// server restart. Item lists are already read fresh from disk on every request; this ensures the
+// type dirs exist and the tool-loader extension is current, and reports the live item counts so the
+// UI can refetch.
+
+const CANONICAL: Record<ItemType, string> = {
+  skills: 'SKILL.md',
+  tools: 'TOOL.md',
+  tasks: 'TASK.md',
+  processes: 'PROCESS.md',
+  extensions: 'index.ts',
+};
+
+function countItems(type: ItemType): number {
+  const dir = itemsDir(type);
+  if (!existsSync(dir)) return 0;
+  let count = 0;
+  for (const entry of readdirSync(dir, { withFileTypes: true })) {
+    if (entry.isDirectory() && existsSync(join(dir, entry.name, CANONICAL[type]))) count++;
+  }
+  return count;
+}
+
+export const rescanRouter = createRouter();
+
+rescanRouter.post('/', async (ctx) => {
+  ensureItemDirs();
+  ensureToolLoader();
+
+  const counts = Object.fromEntries(ITEM_TYPES.map((type) => [type, countItems(type)])) as Record<ItemType, number>;
+
+  return ctx.json({ ok: true, counts });
+});