Add "Run" prefix for unnamed action steps (#36624)

Steps defined with `run:` or `uses:` without an explicit `name:` now
display with a "Run <cmd>" prefix in the Actions log UI, matching GitHub
Actions behavior.

<img width="311" height="236" alt="image"
src="https://github.com/user-attachments/assets/9fde83f5-c43a-4732-ac55-0f4e1fbc1314"
/>

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/actions/task_step.go

@@ -14,7 +14,7 @@ import (
 // ActionTaskStep represents a step of ActionTask
 type ActionTaskStep struct {
 	ID        int64
-	Name      string `xorm:"VARCHAR(255)"`
+	Name      string `xorm:"VARCHAR(255)"` // the step name, for display purpose only, it will be truncated if it is too long
 	TaskID    int64  `xorm:"index unique(task_index)"`
 	Index     int64  `xorm:"index unique(task_index)"`
 	RepoID    int64  `xorm:"index"`