feat(apps): stepped creation wizard, branch previews, and app-creation fixes

This session (frontend focus):
- Rebuild /apps/new as a 4-step wizard (Basics → Configure → Trigger → Review):
  WizardRail, SourceKindPicker card grid, AppManifest review, per-step validation,
  ConfirmDialog-based unsaved-changes guard.
- Extract lib/workload/sourceForms.ts (single source of truth for source_config)
  + {Image,Compose,Static,Dockerfile}SourceForm + StaticDiscoveryWizard; fold the
  /apps/[id] edit form onto the same components (removes the duplication). Add
  vitest + sourceForms unit tests.
- Branch preview environments UI: /chain is_preview/preview_branch + a Preview
  environments panel on /apps/[id] (per-branch URLs, ConfirmDialog teardown, armed
  state); RegistryImagePicker on the registry trigger and the image source.
- Fixes: image-inspect 404 -> admin-gated POST /api/discovery/image/inspect;
  conflict-panel blur flicker; friendly localized discovery errors; CPU/Memory
  label hints; dashboard + /apps "Total workloads" count only source_kind workloads
  (drop stale trigger_kind gate); NPM cert/access-list name cache; EntityPicker
  empty-list guard.
- Update CLAUDE.md frontend conventions + add a Build & Test section.

Also captures pre-existing in-progress platform work (not from this session):
workload notifications, Prometheus metrics export, store lockfile, health probes,
backup hardening, and related store/webhook/scheduler changes.

internal/scheduler/scheduler.go

@@ -27,6 +27,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/alexei/tinyforge/internal/metrics"
 	"github.com/alexei/tinyforge/internal/store"
 	"github.com/alexei/tinyforge/internal/workload/plugin"
 	"github.com/alexei/tinyforge/internal/workload/plugin/trigger/schedule"
@@ -124,6 +125,7 @@ func (s *Scheduler) loop(ctx context.Context) {
 // TickOnce runs a single sweep. Exposed for tests and for the boot
 // kick. On error per-trigger the loop continues with the next row.
 func (s *Scheduler) TickOnce(ctx context.Context) {
+	metrics.SchedulerTicksTotal.Inc()
 	rows, err := s.store.ListTriggers("schedule")
 	if err != nil {
 		slog.Warn("scheduler: list triggers", "error", err)
@@ -226,5 +228,6 @@ func (s *Scheduler) fire(ctx context.Context, t store.Trigger, now time.Time) {
 		slog.Warn("scheduler: dispatch", "trigger", t.Name, "error", err)
 		return
 	}
+	metrics.SchedulerDispatchedTotal.Inc()
 	slog.Info("scheduler: fired", "trigger", t.Name, "kind", t.Kind, "at", ts)
 }