add encryption for the two SQL columns, replace basic DB utils, add USE_DEXIE_DB flag, and start adding SQL everywhere

doc/secure-storage-implementation.md

@@ -144,6 +144,104 @@ try {
 }
 ```
 
+#### A. Modifying Code
+
+When converting from Dexie.js to SQL-based implementation, follow these patterns:
+
+1. **Database Access Pattern**
+   ```typescript
+   // Before (Dexie)
+   const result = await db.table.where("field").equals(value).first();
+   
+   // After (SQL)
+   const platform = PlatformServiceFactory.getInstance();
+   const result = await platform.dbQuery(
+     "SELECT * FROM table WHERE field = ?",
+     [value]
+   );
+   ```
+
+2. **Update Operations**
+   ```typescript
+   // Before (Dexie)
+   await db.table.where("id").equals(id).modify(changes);
+   
+   // After (SQL)
+   const { sql, params } = generateUpdateStatement(
+     changes,
+     "table",
+     "id = ?",
+     [id]
+   );
+   await platform.dbExec(sql, params);
+   ```
+
+3. **Insert Operations**
+   ```typescript
+   // Before (Dexie)
+   await db.table.add(item);
+   
+   // After (SQL)
+   const columns = Object.keys(item);
+   const values = Object.values(item);
+   const placeholders = values.map(() => '?').join(', ');
+   const sql = `INSERT INTO table (${columns.join(', ')}) VALUES (${placeholders})`;
+   await platform.dbExec(sql, values);
+   ```
+
+4. **Delete Operations**
+   ```typescript
+   // Before (Dexie)
+   await db.table.where("id").equals(id).delete();
+   
+   // After (SQL)
+   await platform.dbExec("DELETE FROM table WHERE id = ?", [id]);
+   ```
+
+5. **Result Processing**
+   ```typescript
+   // Before (Dexie)
+   const items = await db.table.toArray();
+   
+   // After (SQL)
+   const result = await platform.dbQuery("SELECT * FROM table");
+   const items = mapColumnsToValues(result.columns, result.values);
+   ```
+
+Key Considerations:
+1. Always use parameterized queries to prevent SQL injection
+2. Use the `generateUpdateStatement` helper for update operations
+3. Use the `mapColumnsToValues` helper for processing query results
+4. Handle transactions explicitly for batch operations
+5. Use appropriate error handling with the StorageError class
+6. Consider platform-specific capabilities when implementing features
+
+Example Migration:
+```typescript
+// Before (Dexie)
+export async function updateSettings(settings: Settings): Promise<void> {
+  await db.settings.put(settings);
+}
+
+// After (SQL)
+export async function updateSettings(settings: Settings): Promise<void> {
+  const platform = PlatformServiceFactory.getInstance();
+  const { sql, params } = generateUpdateStatement(
+    settings,
+    "settings",
+    "id = ?",
+    [settings.id]
+  );
+  await platform.dbExec(sql, params);
+}
+```
+
+Remember to:
+- Create database access code to use the platform service, putting it in front of the Dexie version
+- Instead of removing Dexie-specific code, keep it; if we use the results of the query, then check the USE_DEXIE_DB from app.ts and if it's true then use that instead of the SQL code. 
+- Test thoroughly after migration
+- Consider data migration needs, and warn if there are any potential migration problems
+
 ### 3. Platform Detection
 
 ```typescript