chore(meta): add top-level Makefile for dev workflow

Targets: setup, build, client, server, test, lint, ci, ci-server,
ci-client, clean. Rust targets delegate to cargo, Godot targets
auto-detect godot4/godot on PATH. Client lint and test targets
stubbed pending gdUnit4 and gdlint integration.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -0,0 +1,96 @@
+.PHONY: help setup build client server test lint ci ci-client ci-server clean
+
+# Default
+help:
+	@echo "The Settled Reach — Development Commands"
+	@echo ""
+	@echo "  make setup          Install dev dependencies (Rust, Godot, tooling)"
+	@echo "  make build          Build client and server"
+	@echo "  make client         Run the Godot client"
+	@echo "  make server         Run the Rust simulation server"
+	@echo "  make test           Run all tests"
+	@echo "  make lint           Run all linters"
+	@echo "  make ci             Run full CI pipeline locally"
+	@echo "  make ci-client      Run client CI checks"
+	@echo "  make ci-server      Run server CI checks"
+	@echo "  make clean          Remove build artifacts and caches"
+
+# --- Setup ---
+
+setup: setup-rust setup-godot setup-tooling
+	@echo "Dev environment ready."
+
+setup-rust:
+	@echo "Checking Rust toolchain..."
+	@command -v cargo >/dev/null 2>&1 || { echo "Install Rust: https://rustup.rs"; exit 1; }
+	@rustup component add clippy rustfmt
+
+setup-godot:
+	@echo "Checking Godot..."
+	@command -v godot4 >/dev/null 2>&1 || command -v godot >/dev/null 2>&1 || { echo "Install Godot 4: https://godotengine.org"; exit 1; }
+
+setup-tooling:
+	@echo "Checking tooling dependencies..."
+	@command -v python3 >/dev/null 2>&1 || { echo "Install Python 3"; exit 1; }
+
+# --- Build ---
+
+build: build-server build-client
+
+build-server:
+	cd server && cargo build
+
+build-client:
+	@echo "Client build: Godot exports are configured via the editor."
+	@echo "Use 'make client' to run the client directly."
+
+# --- Run ---
+
+server:
+	cd server && cargo run
+
+client:
+	@if command -v godot4 >/dev/null 2>&1; then \
+		godot4 --path client; \
+	elif command -v godot >/dev/null 2>&1; then \
+		godot --path client; \
+	else \
+		echo "Godot not found. Run 'make setup' first."; exit 1; \
+	fi
+
+# --- Test ---
+
+test: test-server test-client
+
+test-server:
+	cd server && cargo test
+
+test-client:
+	@echo "Client tests run via gdUnit4 inside Godot."
+	@echo "TODO: headless test runner integration"
+
+# --- Lint ---
+
+lint: lint-server lint-client
+
+lint-server:
+	cd server && cargo clippy -- -D warnings
+	cd server && cargo fmt --check
+
+lint-client:
+	@echo "Client lint: TODO — gdlint / gdformat integration"
+
+# --- CI (run locally) ---
+
+ci: ci-server ci-client
+
+ci-server: lint-server build-server test-server
+
+ci-client: lint-client build-client test-client
+
+# --- Clean ---
+
+clean:
+	cd server && cargo clean || true
+	rm -rf .cache/*
+	@echo "Clean complete."