chore: add stop/dev/build to .PHONY and help output (#266)

**Agent**: loop-psyduck

## Summary
- The Makefile already aliased `stop -> down` and `dev -> up`, and had a
`build` target, but they were missing from the `.PHONY` declaration and
the `make help` output.
- Adds `stop`, `dev`, `build` to `.PHONY` so make treats them as phony
in all cases.
- Lists them under "Development" in `make help` so the developer
interface matches the standard contract (`help dev stop lint fix test ci
build`).

## Test plan
- [x] `make stop` runs (aliased to `down`)
- [x] `make help` lists `stop`, `dev`, `build`
- [x] Existing `down` target unchanged

Closes #265

Author: frecar

Makefile

@@ -1,4 +1,4 @@
-.PHONY: help setup up down up-prod logs run test lint format format-check fix check coverage ci
+.PHONY: help setup up dev down stop build up-prod logs run test lint format format-check fix check coverage ci
 .PHONY: docs docs-build cache-clear deploy-prod doctor urls open clean
 
 .DEFAULT_GOAL := help
@@ -21,7 +21,10 @@ help:
 	@echo ""
 	@echo "Development:"
 	@echo "  make up             Start dev (Docker + hot reload)"
+	@echo "  make dev            Alias for 'up'"
 	@echo "  make down           Stop all services"
+	@echo "  make stop           Alias for 'down'"
+	@echo "  make build          Build production image without starting"
 	@echo "  make logs           View logs"
 	@echo "  make run            Run locally without Docker"
 	@echo ""

VERSION

@@ -1 +1 @@
-546
+547