feat: complete release preparation, 10+ ad mediation, CI/CD, and docker deployment

apps/desktop/src/main/ipc/instruction-handlers.ts

@@ -45,6 +45,10 @@ export function registerInstructionHandlers(): void {
   )
 
   ipcMain.handle(IPC_CHANNELS.INSTRUCTION.DELETE, async (_event, params: { id: string }) => {
+    const existing = getCustomInstructionService().getById(params.id)
+    if (!existing) {
+      return ipcError(ErrorCode.ConfigKeyNotFound, `Instruction not found: ${params.id}`)
+    }
     const result = getCustomInstructionService().delete(params.id)
     if (!result) {
       return ipcError(ErrorCode.ConfigWriteFailed, 'Cannot delete builtin instruction')