Initial implementation: host lifecycle + PXE + admin dashboard

Go service for Proxmox homelab cluster provisioning. Handles PXE boot,
Proxmox autoinstall (answer file generation), cluster join via SSH,
and Infrastructure API registration.

- Host state machine (registered → pxe_ready → installing → ready)
- dnsmasq supervisor with MAC-based allowlist
- iPXE script and Proxmox answer file generation
- First-boot phone-home → cluster join → infra registration
- Operation locking with expiry (409 on conflict)
- SSE event hub for real-time dashboard updates
- Admin dashboard (host grid, detail, registration form)
- Config-driven server types with hot-reload
- Docker deployment (multi-stage fat image)

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

internal/api/ui.go

@@ -0,0 +1,159 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strings"
+
+	"provisioning/internal/config"
+	"provisioning/internal/events"
+	"provisioning/internal/model"
+	"provisioning/internal/orchestrator"
+	"provisioning/internal/pxe"
+	"provisioning/internal/statemachine"
+	"provisioning/internal/store"
+
+	"github.com/go-chi/chi/v5"
+)
+
+type UI struct {
+	Hosts       *store.Hosts
+	Ops         *store.Operations
+	Locks       *store.Locks
+	Images      *store.Images
+	Runner      *orchestrator.Runner
+	Hub         *events.Hub
+	PXE         *pxe.Supervisor
+	Config      *config.Config
+	ServerTypes *config.ServerTypeRegistry
+}
+
+func (u *UI) Dashboard(w http.ResponseWriter, r *http.Request) {
+	hosts, _ := u.Hosts.List(r.Context())
+	renderHTML(w, dashboardPage(hosts))
+}
+
+func (u *UI) NewHostForm(w http.ResponseWriter, r *http.Request) {
+	types := u.ServerTypes.Keys()
+	renderHTML(w, hostFormPage(types, "", nil))
+}
+
+func (u *UI) CreateHost(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseForm(); err != nil {
+		http.Error(w, "bad form", http.StatusBadRequest)
+		return
+	}
+	hostname := strings.TrimSpace(r.FormValue("hostname"))
+	mac := strings.TrimSpace(r.FormValue("mac"))
+	serverType := r.FormValue("server_type")
+	notes := r.FormValue("notes")
+
+	var errs []string
+	if hostname == "" {
+		errs = append(errs, "Hostname is required")
+	}
+	if !isValidMAC(mac) {
+		errs = append(errs, "Invalid MAC address format (expected xx:xx:xx:xx:xx:xx)")
+	}
+	if _, ok := u.ServerTypes.Get(serverType); !ok {
+		errs = append(errs, "Invalid server type")
+	}
+	if len(errs) > 0 {
+		types := u.ServerTypes.Keys()
+		renderHTML(w, hostFormPage(types, strings.Join(errs, "; "), &model.Host{
+			Hostname:   hostname,
+			MAC:        mac,
+			ServerType: serverType,
+			Notes:      notes,
+		}))
+		return
+	}
+
+	_, err := u.Hosts.Create(r.Context(), model.Host{
+		Hostname:   hostname,
+		MAC:        mac,
+		ServerType: serverType,
+		Notes:      notes,
+	})
+	if err != nil {
+		types := u.ServerTypes.Keys()
+		renderHTML(w, hostFormPage(types, "Host already exists: "+err.Error(), nil))
+		return
+	}
+
+	hosts, _ := u.Hosts.List(r.Context())
+	_ = u.PXE.Reload(hosts)
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+func (u *UI) HostDetail(w http.ResponseWriter, r *http.Request) {
+	idStr := chi.URLParam(r, "id")
+	var id int64
+	fmt.Sscanf(idStr, "%d", &id)
+
+	host, err := u.Hosts.Get(r.Context(), id)
+	if err != nil {
+		if errors.Is(err, store.ErrNotFound) {
+			http.Error(w, "Host not found", http.StatusNotFound)
+			return
+		}
+		http.Error(w, "Internal error", http.StatusInternalServerError)
+		return
+	}
+	ops, _ := u.Ops.ListByHost(r.Context(), host.ID)
+	renderHTML(w, hostDetailPage(host, ops))
+}
+
+func (u *UI) TriggerRebuild(w http.ResponseWriter, r *http.Request) {
+	idStr := chi.URLParam(r, "id")
+	var id int64
+	fmt.Sscanf(idStr, "%d", &id)
+
+	host, err := u.Hosts.Get(r.Context(), id)
+	if err != nil {
+		http.Error(w, "Host not found", http.StatusNotFound)
+		return
+	}
+
+	locked, _ := u.Locks.IsLocked(r.Context(), host.ID)
+	if locked {
+		http.Redirect(w, r, fmt.Sprintf("/hosts/%d", id), http.StatusSeeOther)
+		return
+	}
+
+	opID, _ := u.Ops.Create(r.Context(), model.Operation{
+		HostID: host.ID,
+		Kind:   model.OpRebuildProxmox,
+	})
+	_ = u.Locks.Acquire(r.Context(), host.ID, opID)
+	u.Runner.Transition(r.Context(), host.ID, statemachine.TriggerRebuildRequested)
+
+	hosts, _ := u.Hosts.List(r.Context())
+	_ = u.PXE.Reload(hosts)
+
+	http.Redirect(w, r, fmt.Sprintf("/hosts/%d", id), http.StatusSeeOther)
+}
+
+func (u *UI) DeleteHost(w http.ResponseWriter, r *http.Request) {
+	idStr := chi.URLParam(r, "id")
+	var id int64
+	fmt.Sscanf(idStr, "%d", &id)
+
+	_ = u.Hosts.Delete(r.Context(), id)
+	hosts, _ := u.Hosts.List(r.Context())
+	_ = u.PXE.Reload(hosts)
+	http.Redirect(w, r, "/", http.StatusSeeOther)
+}
+
+func (u *UI) ImagesPage(w http.ResponseWriter, r *http.Request) {
+	images, _ := u.Images.List(r.Context())
+	renderHTML(w, imagesPage(images))
+}
+
+var macRegex = regexp.MustCompile(`^([0-9a-fA-F]{2}[:\-]){5}[0-9a-fA-F]{2}$`)
+
+func isValidMAC(mac string) bool {
+	return macRegex.MatchString(strings.TrimSpace(mac))
+}