docs(delivery): add Swagger annotations and regenerate API docs

Add Swagger annotations to all 7 delivery handlers. Fix existing
test.go type references (Response -> response.Response). Add swaggo
dependencies to go.mod. Regenerate swagger.json/yaml/docs.go with
delivery endpoints visible in /swagger/index.html.

Relates-to: #97

server/go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/bytedance/sonic v1.14.0 // indirect
 	github.com/bytedance/sonic/loader v0.3.0 // indirect
 	github.com/cloudwego/base64x v0.1.6 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d // indirect
 	github.com/gabriel-vasile/mimetype v1.4.8 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
@@ -45,8 +46,11 @@ require (
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
 	github.com/quic-go/qpack v0.5.1 // indirect
 	github.com/quic-go/quic-go v0.54.0 // indirect
+	github.com/russross/blackfriday/v2 v2.0.1 // indirect
+	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.0 // indirect
+	github.com/urfave/cli/v2 v2.3.0 // indirect
 	go.uber.org/mock v0.5.0 // indirect
 	golang.org/x/arch v0.20.0 // indirect
 	golang.org/x/crypto v0.54.0 // indirect
@@ -58,4 +62,5 @@ require (
 	golang.org/x/tools v0.47.0 // indirect
 	google.golang.org/protobuf v1.36.9 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	sigs.k8s.io/yaml v1.3.0 // indirect
 )