build: make the Makefile aware that this repo needs codegen

The suite reported 26 passed and 17 failed, which reads as broken tests and
was actually a missing build step. *.freezed.dart and lib/**/*.g.dart are
gitignored, so a fresh tree has none of them and most of the suite fails to
compile rather than to assert. After running build_runner the same suite is
452 passed, unchanged.

setup now runs pub get then generate, and generate exists on its own for after
a model change. test guards on a known generated file and says which command
fixes it, because "cannot compile" and "assertion failed" are different
problems and the runner presents them identically.

Co-Authored-By: Claude <noreply@anthropic.com>

Makefile

@@ -13,13 +13,27 @@ help: ## Show this help
 	  | awk 'BEGIN{FS=":.*?## "}{printf "  \033[36m%-14s\033[0m %s\n", $$1, $$2}'
 
 .PHONY: setup
-setup: ## Fetch package dependencies
+setup: ## Fetch dependencies and generate code (run this after a fresh clone)
 	flutter pub get
+	$(MAKE) generate
+
+.PHONY: generate
+generate: ## Regenerate freezed/json_serializable/riverpod sources
+	dart run build_runner build --delete-conflicting-outputs
 
 .PHONY: test
 test: ## Run the widget and unit tests
+	@test -f lib/core/auth/user_preferences.freezed.dart \
+	  || { echo "FAIL — generated sources missing; run: make setup"; exit 1; }
 	flutter test
 
+# Why the guard above: *.freezed.dart and lib/**/*.g.dart are gitignored, so a
+# fresh clone has none of them and most of the suite fails to compile rather
+# than to assert. On 2026-08-09 that read as "26 passed, 17 failed" — which
+# looks like broken tests and is actually a missing build step. After
+# generating, the same suite is 452 passed. A test run that cannot compile
+# should say so in those words.
+
 .PHONY: lint
 lint: ## Static analysis (analysis_options.yaml at the repo root)
 	flutter analyze