Replace Python worker daemon with the Go worker agent

Makefile

@@ -1,15 +1,16 @@
 .DEFAULT_GOAL := help
 
-.PHONY: help demo-ui demo-down demo-logs smoke-two-worker docs docs-serve
+.PHONY: help agent demo-ui demo-down demo-logs smoke-two-worker docs docs-serve
 
 help:
 	@printf '%s\n' \
 	  'SciMesh developer commands:' \
-	  '  make demo-ui                 Start the local UI pipeline demo with 2 workers.' \
-	  '  make demo-ui WORKERS=3       Start the demo with 3 local workers.' \
+	  '  make agent                   Build the Go worker agent (coordinator/bin/worker-agent).' \
+	  '  make demo-ui                 Start the local UI pipeline demo with 2 Go worker agents.' \
+	  '  make demo-ui WORKERS=3       Start the demo with 3 workers.' \
 	  '  make demo-logs               Follow coordinator logs for the demo.' \
 	  '  make demo-down               Stop demo containers and workers.' \
-	  '  make smoke-two-worker        E2E: two workers process 4 shards and the' \
+	  '  make smoke-two-worker        E2E: two Go agents process 4 shards and the' \
 	  '                              result must match the local CLI reference.' \
 	  '  make docs                    Build the MkDocs site into site/.' \
 	  '  make docs-serve              Serve the MkDocs site at http://localhost:8000.' \
@@ -18,6 +19,9 @@ help:
 
 # Convenient entry points from the repository root. Extra settings are passed
 # through, for example: make demo-ui WORKERS=3
+agent:
+	$(MAKE) -C coordinator agent
+
 demo-ui:
 	$(MAKE) -C coordinator demo-ui