Replace inline `npx block-no-verify@1.1.2` with a standalone Node.js
script routed through `run-with-flags.js`, matching every other hook.
Fixes two bugs:
1. npx inherits the project cwd and triggers EBADDEVENGINES in
pnpm-only projects that set devEngines.packageManager.onFail=error.
2. The hook bypassed run-with-flags.js so ECC_DISABLED_HOOKS had no
effect — the isHookEnabled() check never ran.
The new script replicates the full block-no-verify@1.1.2 detection
logic (--no-verify, -n shorthand for commit, core.hooksPath override)
with zero external dependencies.
Closes#1378
