chore: adds a makefile with basic rust targets (#109)

# adds a makefile with basic rust targets

🎀   _make me_.

Author: dylanlott

Makefile

@@ -0,0 +1,47 @@
+# Usage:
+#   make            # build (debug)
+#   make run        # cargo run (debug)
+#   make release    # optimized build
+#   make test       # run unit + integration tests
+#   make fmt        # check & auto‑format
+#   make clippy     # full‑feature lint, deny warnings
+#   make doc        # build docs
+#   make clean      # remove target dir
+# ----------------------------------------------------
+
+CARGO        ?= cargo
+FEATURES     ?= --all-features
+TARGETS      ?= --all-targets
+PROFILE      ?= dev             # override with `make PROFILE=release build`
+CLIPPY_FLAGS ?= $(TARGETS) $(FEATURES) --workspace --profile dev -- -D warnings
+FMT_FLAGS    ?= --all
+
+.PHONY: build release run test clean fmt clippy default
+
+default: build
+
+#-------------------- Core tasks --------------------
+
+build:
+	$(CARGO) build --profile $(PROFILE)
+
+release:
+	$(CARGO) build --release
+
+run:
+	$(CARGO) run --bin zenith-builder-example
+
+test:
+	$(CARGO) test
+
+clean:
+	$(CARGO) clean
+
+fmt:
+	$(CARGO) fmt
+
+clippy:
+	$(CARGO) clippy $(CLIPPY_FLAGS)
+
+tx-submitter:
+	$(CARGO) run --bin transaction-submitter