flake.nix only rewrote @/ aliases but left extensionless relative imports
(./router) in compiled dist/. node dist/index.js (how prod runs) cannot
resolve extensionless ESM specifiers -> ERR_MODULE_NOT_FOUND -> backend
crashlooped (444 restarts, port 4001 dead). Extract the fixer into a shared
scripts/fix-imports.mjs that appends .js to extensionless relative imports and
rewrites @/ aliases, and wire it into backend + discord-gateway build phases.
Verified: fresh tsc + fixer -> node dist/index.js boots; oRPC over /trpc
serves both HTTP POST and WebSocket (config/dashboard/voice/moderation/
media/chatbot/analysis) end-to-end against Postgres + Redis. next build
passes with the oRPC client + partysocket.
