Classify new Contentstack content types in essc discovery

[Mpdreamz]

Why

Contentstack is introducing new content types (blog_landing, tutorial, notebook, series, etc.) that aren't ready to appear in search yet, plus a long tail of reusable component/taxonomy types (hero, accordion_faq, tags_*, etc.) that will never represent a standalone page. PageContentTypes.All is an opt-in allow-list, so none of these are synced today — but the discovery command (essc contentstack types) had no way to distinguish "not yet classified" from "deliberately not a page," making it easy for a genuinely new page-worthy type to go unnoticed.

What

• Added PageContentTypes.Blocked for content types intentionally excluded from sync for now (still being authored, not search-ready).
• Added PageContentTypes.KnownNonPages for component/taxonomy/config content types that are never expected to sync.
• contentstack types now renders a Status column per discovered type (synced / ignored / skipped / unregistered) and exits 1 if any discovered type isn't classified in All, Blocked, or KnownNonPages, so newly-added Contentstack types can't silently go unclassified.
• SyncCommand is unchanged — it already only syncs types explicitly listed in PageContentTypes.All.

[cindychangy]

@Mpdreamz: just saw this from the Slack thread. I noticed a KnownNonPages section, can we add the following to that section:

public static readonly string[] KnownNonPages =
[
    ...
    category_cta
    auto_linking_settings
    auto_linking_term
    glossary_term
  ]

Can we also add glossary to the public static readonly string[] Blocked = section. Thank you!