fix(core): some artifact styles (#13020)

fix AI-299, AI-296

#### PR Dependency Tree


* **PR #13020** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **Style**
* Improved layout alignment in the artifact preview panel for better
visual consistency.
* Enforced a minimum width for linked document banners to ensure
consistent appearance.

* **Bug Fixes**
* Updated artifact and document compose tools so that clicking an
artifact result always opens the preview panel, instead of toggling or
closing it unexpectedly.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/embed-doc/src/embed-linked-doc-block/styles.ts

@@ -168,6 +168,7 @@ export const styles = css`
   .affine-embed-linked-doc-banner {
     margin: 12px 12px 0px 0px;
     width: 204px;
+    min-width: 204px;
     max-width: 100%;
     height: 102px;
     pointer-events: none;