all: support popping a browser from termui

- Add 'browser', 'open', and 'b' command aliases to termui
- Open the current conversation URL in default browser
- Add help documentation for the new command

Add browser launch endpoint to Git server for Docker support.

We'll probably want to set up a proper mux for the no-longer-just-git
server pretty soon.

Co-Authored-By: sketch <hello@sketch.dev>
diff --git a/loop/server/loophttp.go b/loop/server/loophttp.go
index c19f806..82846ac 100644
--- a/loop/server/loophttp.go
+++ b/loop/server/loophttp.go
@@ -77,6 +77,7 @@
 
 type InitRequest struct {
 	HostAddr          string `json:"host_addr"`
+	OutsideHTTP       string `json:"outside_http"`
 	GitRemoteAddr     string `json:"git_remote_addr"`
 	Commit            string `json:"commit"`
 	SSHAuthorizedKeys []byte `json:"ssh_authorized_keys"`
@@ -197,6 +198,7 @@
 			WorkingDir:    "/app",
 			InDocker:      true,
 			Commit:        m.Commit,
+			OutsideHTTP:   m.OutsideHTTP,
 			GitRemoteAddr: m.GitRemoteAddr,
 			HostAddr:      m.HostAddr,
 		}