infra/ci: Add GitHub Actions workflow for staging and production deployment (#256)

## Motivation and Context

- Enable all contributors to manage the infrastructure
- Enable deployments without error-prone manual intervention

## How Has This Been Tested?

Tested by deploying from this test branch, getting CI green and seeing
changes were applied

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

deploy/Makefile

@@ -1,4 +1,4 @@
-.PHONY: help build local-preview local-up staging-preview staging-up prod-preview prod-up
+.PHONY: help build local-login local-preview local-up staging-login staging-preview staging-up prod-login prod-preview prod-up
 
 # Default target
 help: ## Show this help message
@@ -10,22 +10,31 @@ build: ## Build the Pulumi Go program
 	go build
 
 # Local stack commands
-local-preview: build ## Preview local infrastructure changes
+local-login: ## Login to local Pulumi backend
+	pulumi login --local
+
+local-preview: build local-login ## Preview local infrastructure changes
 	PULUMI_CONFIG_PASSPHRASE="" pulumi preview --stack local
 
-local-up: build ## Deploy local infrastructure
+local-up: build local-login ## Deploy local infrastructure
 	PULUMI_CONFIG_PASSPHRASE="" pulumi up --yes --stack local
 
 # Staging stack commands
-staging-preview: build ## Preview staging infrastructure changes
+staging-login: ## Login to staging Pulumi backend
+	pulumi login gs://mcp-registry-staging-pulumi-state
+
+staging-preview: build staging-login ## Preview staging infrastructure changes
 	PULUMI_CONFIG_PASSPHRASE_FILE=passphrase.staging.txt pulumi preview --stack gcpStaging
 
-staging-up: build ## Deploy staging infrastructure
+staging-up: build staging-login ## Deploy staging infrastructure
 	PULUMI_CONFIG_PASSPHRASE_FILE=passphrase.staging.txt pulumi up --yes --stack gcpStaging
 
 # Production stack commands
-prod-preview: build ## Preview production infrastructure changes
+prod-login: ## Login to production Pulumi backend
+	pulumi login gs://mcp-registry-prod-pulumi-state
+
+prod-preview: build prod-login ## Preview production infrastructure changes
 	PULUMI_CONFIG_PASSPHRASE_FILE=passphrase.prod.txt pulumi preview --stack gcpProd
 
-prod-up: build ## Deploy production infrastructure
+prod-up: build prod-login ## Deploy production infrastructure
 	PULUMI_CONFIG_PASSPHRASE_FILE=passphrase.prod.txt pulumi up --yes --stack gcpProd