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/api/auth.go

@@ -16,13 +16,12 @@ import (
 )
 
 // rateLimitedLogin wraps the login handler with per-IP rate limiting.
+// Uses clientIP() so X-Forwarded-For is honored only when the request
+// arrives from a configured trusted-proxy CIDR — preventing remote
+// attackers from spoofing the header to bypass the per-IP login limiter.
 func (s *Server) rateLimitedLogin(rl *rateLimiter) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		ip := r.RemoteAddr
-		if fwd := r.Header.Get("X-Forwarded-For"); fwd != "" {
-			ip = fwd
-		}
-		if !rl.allow(ip) {
+		if !rl.allow(clientIP(r)) {
 			respondError(w, http.StatusTooManyRequests, "too many login attempts, try again later")
 			return
 		}