fix: speed up tests and reduce output verbosity

- Use bcrypt.MinCost in tests instead of DefaultCost (saves ~10s)
- Remove unnecessary 100ms startup sleeps from test server creation (saves ~8s)
- Remove -v flag from Makefile test target to reduce output noise

Handler tests: 24.4s → 13.8s, DB tests: 2.6s → 1.5s
Total make test: 38s → 28s (well under 30s timeout)

Makefile

@@ -32,7 +32,7 @@ fmt-check:
 	@test -z "$$(gofmt -l .)" || (echo "Files not formatted:" && gofmt -l . && exit 1)
 
 test: ensure-web-dist
-	go test -timeout 30s -v -race -cover ./...
+	go test -timeout 30s -race -cover ./...
 
 # check runs all validation without making changes
 # Used by CI and Docker build — fails if anything is wrong