feat(core): add section edit tool (#13313)

Close [AI-396](https://linear.app/affine-design/issue/AI-396)

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

## Summary by CodeRabbit

* **New Features**
* Introduced a "Section Edit" AI tool for expert editing of specific
markdown sections based on user instructions, preserving formatting and
style.
* Added a new interface and UI component for section editing, allowing
users to view, copy, insert, or save edited content directly from chat
interactions.

* **Improvements**
* Enhanced AI chat and tool rendering to support and display section
editing results.
* Updated chat input handling for improved draft management and message
sending order.

* **Other Changes**
* Registered the new section editing tool in the system for seamless
integration.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

oxlint.json

@@ -159,6 +159,7 @@
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+    "unicorn/prefer-array-flat-map": "off",
     "unicorn/no-useless-promise-resolve-reject": "error",
     "unicorn/no-unnecessary-await": "error",
     "unicorn/no-useless-fallback-in-spread": "error",