perf(registratura): lightweight API mode strips base64 attachments from list

ROOT CAUSE: RegistryEntry stores file attachments as base64 strings in JSON.
A single 5MB PDF becomes ~6.7MB of base64. With 6 entries, the exportAll()
endpoint was sending 30-60MB of JSON on every page load  taking 2+ minutes.

Fix: Added ?lightweight=true parameter to /api/storage GET endpoint.
When enabled, stripHeavyFields() recursively removes large 'data' and
'fileData' string fields (>1KB) from JSON values, replacing with '__stripped__'.

Changes:
- /api/storage route.ts: stripHeavyFields() + lightweight query param
- StorageService.export(): accepts { lightweight?: boolean } option
- DatabaseStorageAdapter.export(): passes lightweight flag to API
- LocalStorageAdapter.export(): accepts option (no-op, localStorage is fast)
- useStorage.exportAll(): passes options through
- registry-service.ts: getAllEntries() uses lightweight=true by default
- registry-service.ts: new getFullEntry() loads single entry with full data
- use-registry.ts: exports loadFullEntry() for on-demand full loading
- registratura-module.tsx: handleEdit/handleNavigateEntry load full entry

Result: List loading transfers ~100KB instead of 30-60MB. Editing loads
full data for a single entry on demand (~5-10MB for one entry vs all).

src/modules/registratura/services/registry-service.ts

@@ -8,18 +8,20 @@ export interface RegistryStorage {
   set<T>(key: string, value: T): Promise<void>;
   delete(key: string): Promise<void>;
   list(): Promise<string[]>;
-  exportAll(): Promise<Record<string, unknown>>;
+  exportAll(options?: {
+    lightweight?: boolean;
+  }): Promise<Record<string, unknown>>;
 }
 
 /**
- * Load all registry entries in a SINGLE request.
- * Uses exportAll() which fetches namespace data in one HTTP call,
- * avoiding the N+1 pattern (list keys → get each one individually).
+ * Load all registry entries in a SINGLE lightweight request.
+ * Uses exportAll({ lightweight: true }) which strips base64 attachment data
+ * server-side, reducing payload from potentially 30-60MB to <100KB.
  */
 export async function getAllEntries(
   storage: RegistryStorage,
 ): Promise<RegistryEntry[]> {
-  const all = await storage.exportAll();
+  const all = await storage.exportAll({ lightweight: true });
   const entries: RegistryEntry[] = [];
   for (const [key, value] of Object.entries(all)) {
     if (key.startsWith(STORAGE_PREFIX) && value) {
@@ -30,6 +32,16 @@ export async function getAllEntries(
   return entries;
 }
 
+/**
+ * Load a single full entry (with attachment data) for editing.
+ */
+export async function getFullEntry(
+  storage: RegistryStorage,
+  id: string,
+): Promise<RegistryEntry | null> {
+  return storage.get<RegistryEntry>(`${STORAGE_PREFIX}${id}`);
+}
+
 export async function saveEntry(
   storage: RegistryStorage,
   entry: RegistryEntry,