feat(webhook): fire repository event on repo rename (#38641)

Repository create and delete already fire `repository` webhooks, rename
did not. This adds the `renamed` action with `changes.name.from`
carrying the previous name, and renders it in the chat converters.

Actions workflows are unaffected, they still do not trigger on rename.

AI assistance was used for the implementation and tests.

Fixes https://github.com/go-gitea/gitea/issues/34891.
Co-authored-by: roman s <roman.sukach@dust-labs.com>
Co-authored-by: silverwind <me@silverwind.io>

modules/structs/hook.go

@@ -424,6 +424,8 @@ type ChangesPayload struct {
 	Body *ChangesFromPayload `json:"body,omitempty"`
 	// Changes made to the reference
 	Ref *ChangesFromPayload `json:"ref,omitempty"`
+	// Changes made to the repository name
+	Name *ChangesFromPayload `json:"name,omitempty"`
 	// Changes made to the labels added
 	AddedLabels []*Label `json:"added_labels"`
 	// Changes made to the labels removed
@@ -508,6 +510,8 @@ const (
 	HookRepoCreated HookRepoAction = "created"
 	// HookRepoDeleted deleted
 	HookRepoDeleted HookRepoAction = "deleted"
+	// HookRepoRenamed renamed
+	HookRepoRenamed HookRepoAction = "renamed"
 )
 
 // RepositoryPayload payload for repository webhooks
@@ -520,6 +524,8 @@ type RepositoryPayload struct {
 	Organization *User `json:"organization"`
 	// The user who performed the action
 	Sender *User `json:"sender"`
+	// Changes made to the repository
+	Changes *ChangesPayload `json:"changes,omitempty"`
 }
 
 // JSONPayload JSON representation of the payload