Replaced string literals for thumbnail sizes with GetThumbnailByUriSizeEnum throughout the codebase for improved type safety and consistency. Updated generateThumbnailUrl to accept the enum and added a width map for local URLs. Improved attachment thumbnail display and link formatting.
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR upgrades Gradle to version [9.1.0](https://docs.gradle.org/9.1.0/release-notes.html).
#### Does this PR introduce a user-facing change?
```release-note
升级 Gradle 至 9.1.0
```
#### What type of PR is this?
/area ui
/kind improvement
/milestone 2.21.x
#### What this PR does / why we need it:
Add auto-height prop to formkit textarea to support automatic resizing based on content length.
#### Does this PR introduce a user-facing change?
```release-note
Console 端的部分多行文本输入框支持自动高度。
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR upgrades Spring Boot to [3.5.6](https://github.com/spring-projects/spring-boot/releases/tag/v3.5.6).
#### Does this PR introduce a user-facing change?
```release-note
升级 Spring Boot 至 3.5.6
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR upgrads Lucene to version [10.3.0](https://github.com/apache/lucene/releases/tag/releases%2Flucene%2F10.3.0).
#### Does this PR introduce a user-facing change?
```release-note
升级 Lucene 至 10.3.0
```
#### What type of PR is this?
/kind bug
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR fixes the always show of ghost user in post contributors.
#### Which issue(s) this PR fixes:
Fixes https://github.com/halo-dev/halo/issues/7710
#### Does this PR introduce a user-facing change?
```release-note
修复文章贡献者中始终显示已删除用户的问题
```
#### What type of PR is this?
/kind improvement
/area plugin
/milestone 2.21.x
#### What this PR does / why we need it:
This PR restores context ClassLoader mangement during plugin lifecycle to prevent resource leak.
Meanwhile, it also fixes Class initialization error when starting plugins.
Superseds https://github.com/halo-dev/halo/pull/7725
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/kind improvement
/area core
/area plugin
/milestone 2.21.x
#### What this PR does / why we need it:
This PR adds `io.micrometer:context-propagation` dependency to assist with context propagation across different types of context mechanisms, such as ThreadLocal, Reactor Context, and others.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/area ui
/kind improvement
/milestone 2.21.x
#### What this PR does / why we need it:
In the attachment upload modal, we previously persisted the user’s selected storage policy and group to make future uploads more convenient. However, this overlooked a common usage scenario—users often apply filters for storage policy and group in the attachment list before uploading. Persisting those previous selections could then conflict with the current filters and cause confusion. This PR removes the persistence of selected group and storage policy to avoid such mismatches.
#### Which issue(s) this PR fixes:
Fixes#7713
#### Does this PR introduce a user-facing change?
```release-note
在附件上传组件中取消所选分组和存储策略的持久化，默认选择为附件列表筛选条件相同的策略和分组。
```
#### What type of PR is this?
/kind bug
/area ui
#### What this PR does / why we need it:
目前 Select 组件使用远程接口请求数据时，如果存在分页的数据则分页请求可以超过分页数量。
此 PR 限制了分页请求的次数。
#### Does this PR introduce a user-facing change?
```release-note
解决使用 Select 组件远程请求数据时的分页问题
```
#### What type of PR is this?
/kind bug
/area plugin
/milestone 2.21.x
#### What this PR does / why we need it:
This PR fixes the problem that loading resources from class path during static initialization doesn't work.
#### Does this PR introduce a user-facing change?
```release-note
修复部分场景下无法正常启动插件的问题
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR is a regular update for Spring Boot. See https://github.com/spring-projects/spring-boot/releases/tag/v3.5.5 for more.
#### Does this PR introduce a user-facing change?
```release-note
升级依赖 Spring Boot 至 3.5.5
```
#### What type of PR is this?
/kind improvement
/area core
/milestone 2.21.x
#### What this PR does / why we need it:
This PR allows ListResult to be deserialized with JSON. So we can resolve ListResult response of APIs correctly.
#### Does this PR introduce a user-facing change?
```release-note
None
```
#### What type of PR is this?
/area ui
/milestone 2.21.x
#### What this PR does / why we need it:
Bump rolldown-vite to [7.1.4](https://github.com/vitejs/rolldown-vite/releases/tag/v7.1.4)
#### Does this PR introduce a user-facing change?
```release-note
None
```
Ryan Wang