fix(run-local): frontend fails with opaque "did not become ready" when node_modules is missing

[ratishjain12]

Repro

1. nix develop
2. just run_local --no-doppler on a fresh checkout (no bun install run yet)

Actual

✗ Starting frontend Failed 36s
frontend dev server did not become ready
Error: frontend dev server did not become ready
error: recipe run_local failed on line 13 with exit code 1
All backend services come up healthy — only the frontend step fails, with no indication of why.

Root cause

apps/web/node_modules doesn't exist yet. frontend::start() in tooling/xtask/crates/xtask_local/src/local/frontend.rs spawns bun run dev and polls the port for ~36s; without deps installed, bun/Vite never binds the port in that window, so it hits the generic "did not become ready" bail with no mention of the missing install.

run_local doesn't run bun install anywhere, so this hits every fresh clone.

Proposed fix

In start(), check for apps/web/node_modules before spawning bun run dev and bail with a clear message (mirroring the existing "port already in use" bail right above it), e.g.:

apps/web/node_modules is missing — run \bun install` from the repo root first.`

[synoet]

Yeah we could do this.

[ratishjain12]

raising a PR in few mins :)