feat(store): _saveDisabled latch and stronger corruption-wipe coverage

src/store.js

@@ -11,6 +11,7 @@ export class Store {
     if (!storage) throw new Error('Store requires a storage object');
     this.storage = storage;
     this.onWarn = onWarn;
+    this._saveDisabled = false;
     this.targets = this._loadJson(KEY_TARGETS, {});
     this.history = this._loadJson(KEY_HISTORY, {});
     this.prefs = this._mergePrefs(this._loadJson(KEY_PREFS, null));
@@ -34,11 +35,13 @@ export class Store {
   }
 
   _saveJson(key, value) {
+    if (this._saveDisabled) return false;
     try {
       this.storage.setItem(key, JSON.stringify(value));
       return true;
     } catch (e) {
-      this.onWarn(`[tat] failed to persist ${key}: ${e.message}`);
+      this.onWarn(`[tat] failed to persist ${key}: ${e.message}; further saves disabled for this session`);
+      this._saveDisabled = true;
       return false;
     }
   }