build: update to node 22 and pnpm (#3616)

This commit brings the project to support node 22 which became LTS and
fixes broken builds with typescript 5.7+ until vue-tsc is updated and
replaces npm with pnpm.

- Update tsconfig for node 22
- Pin typescript to 5.6.x to not break vue-tsc
- Replace npm with pnpm (corepack recommended)
- Update Makefile and main workflow for pnpm
- Migrate to eslint 9 flat config
- Fix broken imports
- Exclude non-TS vue files for vue-tsc

frontend/src/stores/upload.ts

@@ -1,7 +1,7 @@
 import { defineStore } from "pinia";
 import { useFileStore } from "./file";
 import { files as api } from "@/api";
-import throttle from "lodash/throttle";
+import { throttle } from "lodash-es";
 import buttons from "@/utils/buttons";
 
 // TODO: make this into a user setting