test: run frontend unit tests in browsers (#38860)

Run them in headless [vitest browser
mode](https://vitest.dev/guide/browser/) in chromium and firefox.
Similar UX than current tests, it's about 5 times as slow (goes from 1s
to 5s on my machine), but definitely worth it as it removes all
happy-dom problems.

---------

Signed-off-by: silverwind <me@silverwind.io>

Makefile

@@ -24,6 +24,9 @@ SHELLCHECK_IMAGE ?= docker.io/koalaman/shellcheck:v0.11.0@sha256:61862eba1fcf09a
 
 CONTAINER_RUNTIME ?= $(shell hash docker >/dev/null 2>&1 && echo docker || echo podman)
 
+PLAYWRIGHT_BROWSERS ?= chromium firefox
+PLAYWRIGHT_FLAGS ?=
+
 HAS_GO := $(shell hash $(GO) > /dev/null 2>&1 && echo yes)
 ifeq ($(HAS_GO), yes)
 	CGO_EXTRA_CFLAGS := -DSQLITE_MAX_VARIABLE_NUMBER=32766
@@ -389,7 +392,7 @@ test-backend: ## test backend files
 	@$(GO) test $(GOTEST_FLAGS) -tags='$(TAGS)' $(GO_TEST_PACKAGES)
 
 .PHONY: test-frontend
-test-frontend: node_modules ## test frontend files
+test-frontend: playwright ## test frontend files
 	pnpm exec vitest
 
 .PHONY: test-check
@@ -484,11 +487,11 @@ migrations.individual.test\#%:
 
 .PHONY: playwright
 playwright: deps-frontend
-	@CONTAINER_RUNTIME=$(CONTAINER_RUNTIME) ./tools/test-e2e.sh install
+	@./tools/playwright.sh $(PLAYWRIGHT_FLAGS) $(PLAYWRIGHT_BROWSERS)
 
 .PHONY: test-e2e
 test-e2e: playwright frontend backend
-	@CONTAINER_RUNTIME=$(CONTAINER_RUNTIME) EXECUTABLE=$(EXECUTABLE) ./tools/test-e2e.sh run $(GITEA_TEST_E2E_FLAGS)
+	@CONTAINER_RUNTIME=$(CONTAINER_RUNTIME) EXECUTABLE=$(EXECUTABLE) ./tools/test-e2e.sh $(GITEA_TEST_E2E_FLAGS)
 
 .PHONY: build
 build: frontend backend ## build everything