A build is taken in where its outcome is heard, and the build tool answers at once (issue 176)

The console's `build` tool answered "no build machine answered within 0s", handed a forge path to
git as written, and a build heard afterwards was recorded and never registered: recording and
registration lived only in the waiting caller, and the tool did not wait.

Now one function takes a build's outcome in — records it, parses the manifest, refuses a definition
naming an installation, registers the module with its source as the seat and path the request
carried — and both the waiting command and the daemon that follows the role's `built` event call
it. `build --wait 0` asks and returns with the id; `builds --log <id>` follows it. The seat verb
says `--self` for a repository given without a scheme.

cmd/mesh-builder/main.go

@@ -166,7 +166,7 @@ func answer(ctx context.Context, publisher builder.Publisher, on, workspace stri
 
 	result := link.BuildResult{
 		ID: request.ID, Repository: request.Repository, Path: request.Path,
-		Ref: request.Ref, On: on,
+		Ref: request.Ref, On: on, Source: request.Source,
 	}
 	what := "building " + request.Repository
 	if request.Path != "" {