i18n: Translate all Chinese to English across the codebase

Translate Chinese comments, log/error messages, validator labels and
Swagger annotations to English throughout the source code, generated
Swagger docs, config files and CI workflows.

Make the English README primary: README.md now holds the English docs
and README_EN.md holds the Chinese version, with cross-language links
updated accordingly.

Note: the generated docs/ swagger files were translated in place; run
`go generate ./...` (swag init) to regenerate them from the now-English
annotations when a Go toolchain is available.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

http/request/api/peer.go

@@ -36,7 +36,7 @@ func (pf *PeerForm) ToPeer() *model.Peer {
 	}
 }
 
-// PersonalAddressBookForm 个人地址簿表单
+// PersonalAddressBookForm personal address book form
 type PersonalAddressBookForm struct {
 	model.AddressBook
 	ForceAlwaysRelay string `json:"forceAlwaysRelay"`