[Clipclops] New routes with placeholder screens (#3725)

* add new routes with placeholder screens

* gate content

* add filled envelope style

* swap filled state

* switch to `useAgent`

bskyweb/cmd/bskyweb/server.go

@@ -200,6 +200,8 @@ func serve(cctx *cli.Context) error {
 	e.GET("/support/community-guidelines", server.WebGeneric)
 	e.GET("/support/copyright", server.WebGeneric)
 	e.GET("/intent/compose", server.WebGeneric)
+	e.GET("/messages", server.WebGeneric)
+	e.GET("/messages/:conversation", server.WebGeneric)
 
 	// profile endpoints; only first populates info
 	e.GET("/profile/:handleOrDID", server.WebProfile)