initial agent-mgr: app builder platform MVP

Go API server + Preact UI + Claude Code adapter.
- App-centric model (ideas, not repos)
- AgentProvider interface for multi-agent support
- K8s pod lifecycle for sandboxed agent sessions
- Gitea integration (create repos, push branches)
- WebSocket streaming for live session output
- Woodpecker CI/CD pipelines (kaniko build + kubectl deploy)

Makefile

@@ -0,0 +1,32 @@
+.PHONY: build build-ui build-go run clean docker docker-runner
+
+# Build UI, then Go binary
+build: build-ui build-go
+
+build-ui:
+	cd ui && npm ci --ignore-scripts && npm run build
+
+build-go:
+	go build -o bin/agent-mgr ./cmd/agent-mgr
+
+run: build
+	./bin/agent-mgr
+
+clean:
+	rm -rf bin/ ui/dist/index.js ui/node_modules
+
+# Docker images
+docker:
+	docker build -f docker/Dockerfile -t agent-mgr .
+
+docker-runner:
+	docker build -f docker/Dockerfile.claude-runner -t claude-code-runner docker/
+
+# Development: run with local kubeconfig
+dev: build-ui
+	KUBECONFIG=~/.kube/n2d-1-config \
+	DATABASE_URL=postgres://localhost:5432/agent_mgr_db?sslmode=disable \
+	GITEA_URL=https://git.asp.now \
+	GITEA_TOKEN= \
+	GITEA_BOT_USER=agent-mgr-bot \
+	go run ./cmd/agent-mgr