feat(dashboardAPI): resolve Grafana folder by name (fixes stale folderUid 400s)

A pinned folderUid goes stale whenever Grafana is rebuilt — the same-named
folder returns with a fresh uid and every dashboard upsert then 400s
"folder not found", silently dropping all generated dashboards.

Add a folderTitle config field: when set, resolveFolderUid() looks the folder
up by name (GET /api/folders), creates it if absent (POST /api/folders),
caches the uid for the process, and falls back to the configured folderUid on
any failure (never worse than the pinned behavior). The emit handlers
(registerChild/regenerateDashboard/emitDashboardsFor) are now async and await
the resolution. folderUid retained as an explicit override/fallback.

Locked by slice48-folder-resolve-by-name; existing emit tests made async.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/basic/slice48-folder-resolve-by-name.basic.test.js

@@ -0,0 +1,100 @@
+'use strict';
+
+const test = require('node:test');
+const assert = require('node:assert/strict');
+
+const DashboardApi = require('../../src/specificClass.js');
+const { registerChild } = require('../../src/commands/handlers.js');
+
+// Minimal fetch double. `routes` maps `${method} ${pathname}` to a response
+// descriptor { ok, status, body }. Records every call for assertions.
+function makeFetch(routes) {
+  const calls = [];
+  const fetchImpl = async (url, opts = {}) => {
+    const method = opts.method || 'GET';
+    const { pathname } = new URL(url);
+    calls.push({ method, pathname, body: opts.body });
+    const r = routes[`${method} ${pathname}`];
+    if (!r) return { ok: false, status: 404, json: async () => ({ message: 'not found' }) };
+    if (typeof r === 'function') return r();
+    return { ok: r.ok ?? true, status: r.status ?? 200, json: async () => r.body };
+  };
+  fetchImpl.calls = calls;
+  return fetchImpl;
+}
+
+function api(grafanaConnector) {
+  return new DashboardApi({ grafanaConnector });
+}
+
+test('no folderTitle → returns configured folderUid without any fetch (legacy path)', async () => {
+  const a = api({ folderUid: 'pinned-uid' });
+  const fetchImpl = makeFetch({});
+  const uid = await a.resolveFolderUid({ fetchImpl });
+  assert.equal(uid, 'pinned-uid');
+  assert.equal(fetchImpl.calls.length, 0, 'must not call Grafana when no folderTitle is set');
+});
+
+test('folderTitle matches an existing folder (case-insensitive) → returns its uid', async () => {
+  const a = api({ folderTitle: 'EVOLV' });
+  const fetchImpl = makeFetch({
+    'GET /api/folders': { body: [{ title: 'Other', uid: 'x' }, { title: 'evolv', uid: 'bfncls6af0b9cb' }] },
+  });
+  const uid = await a.resolveFolderUid({ fetchImpl });
+  assert.equal(uid, 'bfncls6af0b9cb');
+  assert.equal(fetchImpl.calls.filter((c) => c.method === 'POST').length, 0, 'must not create when found');
+});
+
+test('resolution is cached → second call makes no further fetch', async () => {
+  const a = api({ folderTitle: 'EVOLV' });
+  const fetchImpl = makeFetch({ 'GET /api/folders': { body: [{ title: 'EVOLV', uid: 'u1' }] } });
+  await a.resolveFolderUid({ fetchImpl });
+  await a.resolveFolderUid({ fetchImpl });
+  assert.equal(fetchImpl.calls.length, 1, 'second resolve should hit the cache');
+});
+
+test('folder absent → creates it by name and returns the new uid', async () => {
+  const a = api({ folderTitle: 'EVOLV' });
+  const fetchImpl = makeFetch({
+    'GET /api/folders': { body: [{ title: 'Other', uid: 'x' }] },
+    'POST /api/folders': { status: 200, body: { uid: 'created-uid', title: 'EVOLV' } },
+  });
+  const uid = await a.resolveFolderUid({ fetchImpl });
+  assert.equal(uid, 'created-uid');
+  const post = fetchImpl.calls.find((c) => c.method === 'POST');
+  assert.equal(JSON.parse(post.body).title, 'EVOLV');
+});
+
+test('fetch throws → falls back to configured folderUid (never worse than pinned)', async () => {
+  const a = api({ folderTitle: 'EVOLV', folderUid: 'fallback-uid' });
+  const fetchImpl = async () => { throw new Error('ECONNREFUSED'); };
+  const uid = await a.resolveFolderUid({ fetchImpl });
+  assert.equal(uid, 'fallback-uid');
+});
+
+test('no fetch implementation available → falls back to configured folderUid', async () => {
+  const a = api({ folderTitle: 'EVOLV', folderUid: 'fallback-uid' });
+  // Pass an explicit non-function (not undefined, which would trigger the
+  // globalThis.fetch default) to exercise the "no fetch available" branch.
+  const uid = await a.resolveFolderUid({ fetchImpl: null });
+  assert.equal(uid, 'fallback-uid');
+});
+
+test('emit path stamps the resolved folderUid onto every upsert payload', async () => {
+  const a = api({ folderTitle: 'EVOLV' });
+  // Force a deterministic resolution without standing up fetch.
+  a.resolveFolderUid = async () => 'resolved-folder-uid';
+
+  const childSource = {
+    config: { general: { id: 'm1', name: 'Level' }, functionality: { softwareType: 'measurement' } },
+  };
+  const sent = [];
+  const ctx = { node: { id: 'dapi' }, send: (m) => sent.push(m) };
+  await registerChild(a, { payload: childSource }, ctx);
+
+  assert.ok(sent.length >= 1, 'should emit at least one create');
+  for (const m of sent) {
+    assert.equal(m.topic, 'create');
+    assert.equal(m.payload.folderUid, 'resolved-folder-uid');
+  }
+});