Fix Dockerfile: use mcr.microsoft.com/dotnet/runtime:8.0 as base, add Makefile

Dockerfile:
- Final stage now FROM mcr.microsoft.com/dotnet/runtime:8.0 instead of python:3.12-slim
  + MS apt repo. Reason: packages.microsoft.com GPG key uses SHA1 which Debian trixie
  rejects since 2026-02-01. The official MS container image has no signing issue.
- Add python3 + pip3 + wget on top of dotnet base (bookworm)
- pip3 install --break-system-packages for debian bookworm compatibility

Makefile targets:
  make build        - build image locally
  make rebuild      - force no-cache build
  make run          - build + start container with port mappings
  make run-quick    - start without rebuilding
  make stop/restart - container lifecycle
  make logs         - follow logs
  make shell        - bash into running container
  make health       - curl health endpoint
  make smoke        - end-to-end TCP + health test (scripts/smoke_test.sh)
  make test         - unit tests (pytest, no Docker)
  make ps/ports     - status helpers
  make clean        - stop + remove image

Makefile

@@ -0,0 +1,109 @@
+IMAGE   := ilsp-local
+TAG     := dev
+CONTAINER := ilsp-dev
+
+PYTHON_PORT := 2087
+BICEP_PORT  := 2088
+HEALTH_PORT := 2089
+
+# External services (used at container startup for catalog fetching)
+DEVOPS_MCP_URL ?= https://devops-mcp.i80.dk
+
+.PHONY: build run stop restart logs shell test smoke clean help
+
+## ── Build ────────────────────────────────────────────────────────────────────
+
+build:                ## Build Docker image locally (no push)
+	docker build -t $(IMAGE):$(TAG) .
+
+rebuild:              ## Force rebuild (no cache)
+	docker build --no-cache -t $(IMAGE):$(TAG) .
+
+## ── Run ──────────────────────────────────────────────────────────────────────
+
+run: stop             ## Build and start container (rebuilds image)
+	$(MAKE) build
+	docker run -d \
+		--name $(CONTAINER) \
+		-p $(PYTHON_PORT):$(PYTHON_PORT) \
+		-p $(BICEP_PORT):$(BICEP_PORT) \
+		-p $(HEALTH_PORT):$(HEALTH_PORT) \
+		-e DEVOPS_MCP_URL=$(DEVOPS_MCP_URL) \
+		-e PYTHONUNBUFFERED=1 \
+		$(IMAGE):$(TAG)
+	@echo ""
+	@echo "  Container started — waiting for health check..."
+	@sleep 5
+	@$(MAKE) health
+
+run-quick:            ## Start container without rebuilding image
+	$(MAKE) stop
+	docker run -d \
+		--name $(CONTAINER) \
+		-p $(PYTHON_PORT):$(PYTHON_PORT) \
+		-p $(BICEP_PORT):$(BICEP_PORT) \
+		-p $(HEALTH_PORT):$(HEALTH_PORT) \
+		-e DEVOPS_MCP_URL=$(DEVOPS_MCP_URL) \
+		-e PYTHONUNBUFFERED=1 \
+		$(IMAGE):$(TAG)
+	@sleep 5
+	@$(MAKE) health
+
+stop:                 ## Stop and remove container (if running)
+	-docker stop $(CONTAINER) 2>/dev/null
+	-docker rm   $(CONTAINER) 2>/dev/null
+
+restart: stop run-quick  ## Restart container without rebuilding
+
+logs:                 ## Follow container logs
+	docker logs -f $(CONTAINER)
+
+logs-tail:            ## Show last 50 lines of logs
+	docker logs --tail 50 $(CONTAINER)
+
+shell:                ## Open bash inside running container
+	docker exec -it $(CONTAINER) bash
+
+## ── Health & Testing ─────────────────────────────────────────────────────────
+
+health:               ## Check health endpoint
+	@curl -sf http://localhost:$(HEALTH_PORT)/health | python3 -m json.tool \
+		|| echo "  ✗ Health endpoint not reachable — is the container running? (make run)"
+
+smoke:                ## Run end-to-end smoke test against local container
+	bash scripts/smoke_test.sh localhost
+
+test:                 ## Run unit tests (local Python, no Docker needed)
+	python3 -m pytest tests/ -v
+
+## ── Status ───────────────────────────────────────────────────────────────────
+
+ps:                   ## Show running container status
+	@docker ps --filter name=$(CONTAINER) --format "table {{.Names}}\t{{.Status}}\t{{.Ports}}"
+
+ports:                ## Show port mappings
+	@echo "  Python LSP : localhost:$(PYTHON_PORT)  (TCP)"
+	@echo "  Bicep  LSP : localhost:$(BICEP_PORT)   (TCP)"
+	@echo "  Health     : http://localhost:$(HEALTH_PORT)/health"
+
+## ── Cleanup ──────────────────────────────────────────────────────────────────
+
+clean: stop           ## Stop container and remove local image
+	-docker rmi $(IMAGE):$(TAG) 2>/dev/null
+
+## ── Help ─────────────────────────────────────────────────────────────────────
+
+help:                 ## Show this help
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' Makefile \
+		| awk 'BEGIN {FS = ":.*?## "}; {printf "  \033[36m%-14s\033[0m %s\n", $$1, $$2}'
+	@echo ""
+	@echo "  Env vars:"
+	@echo "    DEVOPS_MCP_URL  (default: $(DEVOPS_MCP_URL))"
+	@echo ""
+	@echo "  Examples:"
+	@echo "    make run              # build + start"
+	@echo "    make logs             # follow logs"
+	@echo "    make smoke            # end-to-end test"
+	@echo "    DEVOPS_MCP_URL=http://localhost:8000 make run  # point at local MCP"
+
+.DEFAULT_GOAL := help