Move Odin renderer into gui/ with per-project Makefiles

Each sub-project (gui, api, infra) now owns its own Makefile, and the
root Makefile is a lean delegator for the base commands (run, build,
test, clean, fmt). Odin source, deps, and web assets live under gui/
(gui/src, gui/lib, gui/www), with scripts kept under gui/scripts for
build tooling only.

infra/Makefile

@@ -0,0 +1,35 @@
+# infra/Makefile — Go + Pulumi infrastructure-as-code.
+#
+# Driven directly with `make -C infra <target>` (or via the root Makefile's
+# `infra-*` convenience targets). Targets that interact with the live cluster
+# run Pulumi against the stack defined in Pulumi.yaml.
+
+.PHONY: help preview up down refresh static test clean tidy
+
+help: ## List available targets
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | \
+		awk 'BEGIN {FS = ":.*?## "}; {printf "  \033[36m%-18s\033[0m %s\n", $$1, $$2}'
+
+preview: ## Preview infra changes against the cluster
+	pulumi preview
+
+up: ## Deploy/update infra
+	pulumi up
+
+down: ## Tear down the stack's resources
+	pulumi destroy
+
+refresh: ## Refresh Pulumi state against the live cluster
+	pulumi refresh
+
+static: ## Typecheck + vet without Pulumi
+	go build -o /dev/null . && go vet ./...
+
+test: ## Run Go unit tests
+	go test ./...
+
+clean: ## Remove local Go build artifact
+	rm -f desi-explorer-infra
+
+tidy: ## Tidy Go modules
+	go mod tidy