feat: add benchmark target to Makefile

Add bench target to run Go benchmarks for all samples in the samples folder.
Uses fixed iterations (10x) and 4 CPU cores for consistent results.

Makefile

@@ -1,7 +1,7 @@
 BINARY_NAME=lambda
 TEST=simple
 
-.PHONY: help build run profile explain graph docs clean
+.PHONY: help build run profile explain graph docs bench clean
 .DEFAULT_GOAL := help
 .SILENT:
 
@@ -13,6 +13,7 @@ help:
 	echo "  explain  - Build and run with explanation mode and profiling"
 	echo "  graph    - Generate and open CPU profile visualization"
 	echo "  docs     - Start local godoc server on port 6060"
+	echo "  bench    - Run benchmarks for all samples"
 	echo "  clean    - Remove all build artifacts"
 
 build:
@@ -37,6 +38,9 @@ docs:
 	echo ">>> View at 'http://localhost:6060/pkg/git.maximhutz.com/max/lambda/'"
 	go run golang.org/x/tools/cmd/godoc@latest -http=:6060
 
+bench:
+	go test -bench=. -benchtime=10x -cpu=4 ./cmd/lambda
+
 clean:
 	rm -f ${BINARY_NAME}
 	rm -f program.out