fix: respect user's npm registry configuration in update check

[serhiizghama]

Problem

The startup update check in src/bin/check-latest-version.ts hardcodes https://registry.npmjs.org/chrome-devtools-mcp/latest. Users behind corporate proxies or on a private registry (e.g. JFrog Artifactory) cannot reach that URL — the request silently fails on every startup, and they lose update notifications unless they set CHROME_DEVTOOLS_MCP_NO_UPDATE_CHECKS=1.

Fixes #1943.

The earlier discussion on that issue surfaced two competing approaches:

• Reading only npm_config_registry. The maintainer pointed out this only covers npx / npm run invocations, not direct CLI use.
• Pulling in @npmcli/config. Solves all cases but adds a runtime dependency.

This PR uses a third approach suggested in the issue: shell out to npm config get registry. That command:

• Honors .npmrc files at every scope (global, user, project) and respects npm_config_registry.
• Works the same regardless of how the CLI is invoked (direct, npx, npm run).
• Adds no new dependency.
• Runs at most once per 24 hours from a detached process, so the shell-out cost is negligible.

Solution

Add a small getRegistry() helper that runs npm config get registry with a 5 s timeout and validates the result before using it. Fall back to the hardcoded public registry when:

• npm is not on PATH,
• the command times out or errors,
• the value is empty, "undefined", or not an http(s) URL.

The fetch URL is then composed from that resolved registry.

Testing

• npm run typecheck — passes
• npm run check-format — passes
• npm run build — passes
• node --test build/tests/check-for-updates.test.js — 6/6 pass (no regressions in the existing test suite for this area)
• Manual: ran node build/src/bin/check-latest-version.js /tmp/out.json against the public registry → wrote {"version":"0.25.0"}. Re-ran with npm_config_registry=https://example.com → fetch fails silently as expected, no cache written.

(Unrelated E2E browser tests in tests/e2e/chrome-devtools-commands.test.js fail in my local environment; they appear environment-dependent and are not touched by this change.)