fix(pv-scripts): pin fork-ts-checker to 9.0.3 (fix macOS EMFILE)

[friewerts]

Problem

On macOS pv-scripts dev crashes with EMFILE: too many open files, watch as soon as a page compiling several (lazy) bundles is opened, when the TS type-check is enabled. Regression introduced in pv-scripts 6 (fine in 5.0.1).

Error: EMFILE: too many open files, watch
    at FSWatcher._handle.onchange (node:internal/fs/watchers)
    at FSWatcher._handleError (node_modules/chokidar/index.js:539:18)
    at NodeFsHandler._boundHandleError (node_modules/chokidar/handler.js:300:49)

Root cause

• fork-ts-checker-webpack-plugin@9.1.0 bumped its chokidar dependency 3 → 4.
• chokidar@4 dropped fsevents. On macOS it therefore falls back to native fs.watch, which opens one file descriptor per watched directory instead of a single fsevents stream.
• fork-ts-checker watches every tsconfig wildcard directory with its own chokidar.watch(). A tsconfig.json without include makes TypeScript watch the whole project root incl. node_modules, so the FD count explodes and exhausts the per-process limit.

The regression is specific to 9.1.0 — versions 9.0.0–9.0.3 use chokidar@^3.5.3 (with fsevents).

Fix

Pin fork-ts-checker-webpack-plugin to 9.0.3 (last release on the chokidar-3 line). The entire diff 9.0.3 → 9.1.0 is: the chokidar major bump, a version string, and one cosmetic log message — the watch code is byte-identical. So this is a no-risk, transparent fix shipped to all consumers (no consumer-side overrides required).

Also documents enableTypeCheck (was missing from the config table) and adds a Troubleshooting section (tsconfig include, overrides, enableTypeCheck: false).

Verification (macOS, real consumer)

Test	before (9.1.0 / chokidar 4)	after (9.0.3 / chokidar 3)
pv-scripts dev + open the crashing styleguide URL	EMFILE crash @ ~12s	stable 150s, 0 EMFILE
open FDs of the dev process	crash	~54–60 (fsevents)
isolated watch of the real consumer tree	EMFILE @ 9,879 FDs	22 FDs
type-check	—	catches TS2322, passes clean code

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