Check PostHog loading

For each URL, navigates a real browser to the page, waits for PostHog to initialize, and reports:

• Whether window.posthog is defined and __loaded.
• Which load method was used: head_snippet, snippet, array_js_only, or none.
• Where in the document the snippet lives (head / body).
• The init config: api_key, api_host, person_profiles.
• Runtime state including the assigned distinct_id.

When to use

• Sanity-check a fresh install — does the snippet actually load on every page?
• After a page-template change — did one page lose the snippet?
• When investigating split data — are some pages pointing at a different api_host or api_key than others?
• Onboarding a new customer — confirm SDK is wired up before debugging events.