refactor: enforce import directions and expose source factories

src/data/feedState.js

@@ -0,0 +1,54 @@
+import { GUIDANCE_STATUSES } from '../loadingFeedback.js';
+
+/**
+ * Normalize heterogeneous layer stats into one honest control-chip state.
+ * @param {object|null} stats Layer getStats() result.
+ * @returns {'nominal'|'loading'|'degraded'|'stale'|'fallback'|'unavailable'} Feed state.
+ */
+export function layerFeedState(stats = {}) {
+  const state = stats || {};
+  const status =
+    typeof state.status === 'string' ? state.status.toLowerCase() : '';
+  const source = `${state.source || ''} ${state.coverage || ''}`;
+  const hasExplicitFallback = typeof state.fallback === 'boolean';
+  const hasPriorData = Number(state.count) > 0 || Boolean(state.lastUpdate);
+  const presentedError =
+    state.error || state.lastError || state.managerRefreshError;
+  if (['unavailable', 'offline', 'down', 'error'].includes(status))
+    return 'unavailable';
+  if (
+    (presentedError ||
+      state.unavailable === true ||
+      state.available === false) &&
+    !hasPriorData &&
+    !GUIDANCE_STATUSES.includes(status)
+  ) {
+    return 'unavailable';
+  }
+  if (state.loading) return 'loading';
+  // Guidance states ask the user to act (zoom in, run a search) — normal
+  // operation, not feed faults. One honesty carve-out: layers keep their
+  // rendered records through the guidance state, so a genuinely stale cache
+  // still reads STALE; a guidance prompt alone never reads DEGRADED.
+  if (GUIDANCE_STATUSES.includes(status)) {
+    return state.stale ? 'stale' : 'nominal';
+  }
+  if (
+    state.fallback === true ||
+    status === 'fallback' ||
+    state.mode === 'sim' ||
+    /\bfallback\b/i.test(source) ||
+    (!hasExplicitFallback && /\badsb\.lol\b/i.test(source))
+  ) {
+    return 'fallback';
+  }
+  if (state.stale || status === 'stale') return 'stale';
+  if (
+    state.degraded ||
+    presentedError ||
+    state.unavailable === true ||
+    state.available === false
+  )
+    return 'degraded';
+  return 'nominal';
+}