SDK regeneration (#168)

* [fern-generated] Update SDK

Generated by Fern
CLI Version: unknown
Generators:
  - fernapi/fern-python-sdk: 4.25.6

* [fern-replay] advance lockfile

* docs(examples): add knowledge-stores + responses (Agents API) examples

Ported from tl-openapi/sdk-testing (prod-verified). Use the TwelveLabs client
(BaseClient already exposes knowledge_stores/responses). Covers KS CRUD, items,
collections, search incl. include_metadata, and responses incl. streaming.

NOTE: requires the 1.3.0 release (adds these resources).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* docs(examples): clean internal comments; exercise video+image; show item creation

- Remove internal-facing comments (dev/prod env references, 'as of this writing',
  observed rate numbers, image-not-supported notes).
- Add both a video AND an image item (images are supported); drop video-only.
- Make knowledge_store_items.create an explicit, visible step in the items demo
  instead of hiding it in the setup helper.
- Simplify pagination (no defensive/internal commentary).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(examples): satisfy mypy on Optional id fields from generated client

assets.create()/knowledge_stores.create()/knowledge_store_items.create()
return Optional[str] ids; narrow with asserts before use as str.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

---------

Co-authored-by: fern-api[bot] <115122769+fern-api[bot]@users.noreply.github.com>
Co-authored-by: park-yeonhoo <park@twelvelabs.io>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>