Stand-in import of elffuss/claw

One parentless commit with only the files that the open seed tasks touch and the modules they import.
The full squashed import (SPEC 8.6) is a later step: this tree is not the cutoff tree.

T2T-StandIn-Source-Commit: 70b800e87ef05a9574bf2ae8226cef90015dbe21

web/js/db.js

@@ -0,0 +1,32 @@
+// IndexedDB mínima: stores clave→valor.
+const NAME = 'elffuss', VERSION = 2;
+const STORES = ['kv', 'apps', 'tasks', 'vault', 'fs', 'memory'];
+let dbPromise = null;
+
+function open() {
+  if (dbPromise) return dbPromise;
+  dbPromise = new Promise((resolve, reject) => {
+    const req = indexedDB.open(NAME, VERSION);
+    req.onupgradeneeded = () => {
+      for (const s of STORES)
+        if (!req.result.objectStoreNames.contains(s)) req.result.createObjectStore(s);
+    };
+    req.onsuccess = () => resolve(req.result);
+    req.onerror = () => reject(req.error);
+  });
+  return dbPromise;
+}
+
+function tx(store, mode, fn) {
+  return open().then(db => new Promise((resolve, reject) => {
+    const req = fn(db.transaction(store, mode).objectStore(store));
+    req.onsuccess = () => resolve(req.result);
+    req.onerror = () => reject(req.error);
+  }));
+}
+
+export const get  = (store, key)      => tx(store, 'readonly',  s => s.get(key));
+export const set  = (store, key, val) => tx(store, 'readwrite', s => s.put(val, key));
+export const del  = (store, key)      => tx(store, 'readwrite', s => s.delete(key));
+export const keys = (store)           => tx(store, 'readonly',  s => s.getAllKeys());
+export const all  = (store)           => tx(store, 'readonly',  s => s.getAll());