fix: reconcile code-defined collection types on cached bootstrap #1014

Summary

When CACHE_KV contains the versioned bootstrap marker, SonicJS restores the in-memory collection registry but skips
autoRegisterCollectionDocumentTypes().

A newly added code-defined collection therefore appears in the admin UI, but lacks a corresponding document_types record.
Document-backed operations, including slug availability checks, then fail.

Reproduction

Tested at commit 646c75b2 with Node v22.22.0 and npm 10.9.4.

1. Start an app with CACHE_KV enabled, allowing _sonicjs_bootstrap_v<version> to be created.
2. Add and register a new code-defined collection without changing SONICJS_VERSION.
3. Restart the app and create content in the new collection.
4. Enter a value in its URL Slug field.

The content form loads, but slug validation requests return:

GET /api/content/check-slug?... 400 Bad Request
{"error":"Collection not found or not document-backed"}

The collection is present in the in-memory registry but absent from document_types.

Expected behavior

Cached bootstrap should reconcile registered collections with document_types, so newly added collections work with document-
backed APIs immediately after restart.

Proposed fix

In the kvDone === '1' bootstrap fast path, call:

await autoRegisterCollectionDocumentTypes(c.env.DB)

after hydrating and registering the collection configs.