Root cause: the tools dir installed typescript@latest, now TypeScript 7 (native port, no typescript.js/tsserver.js/ts.server), so @vue/language-server 3 crashed on ts.server.protocol and restarted forever; Volar 3 hybrid mode also needs tsserver/request forwarding, which we never answered.
Fix: pin TS-as-library servers to typescript@<7 and keep shared deps on uninstall; pick a usable tsdk (setting / bundled / project, --tsdk); bridge tsserver/request to vtsls with @vue/typescript-plugin (null when vtsls is absent); answer workspace/configuration for section ""; stop restarting after 3 consecutive early crashes (IDEA); crash summary starts at the exception line.
Siblings covered: typescript-language-server and svelte-language-server (same TS 7 break), vtsls config, install hints in language TOMLs.
Verified: scoped cargo tests, real-server tests (vue-language-server 3.3.13 + vtsls), in-app on macOS (server running, no crash loop). Not verified on Windows.
Claude-Session: https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn
l0ng-ai