feat(go-crm): industrial terminal-core UI redesign

Complete visual overhaul of the go-crm web interface:

- New shared layout system (internal/templates/ui.go) with dark zinc
  industrial theme, JetBrains Mono typography, grid/noise textures
- Redesigned all pages: Dashboard, Login/Signup, Clients, Customers,
  Services, Scheduling, Payments, Questions, Answers, Leads,
  Review Queue, Report, Keyword Mapping
- Tailwind CSS via CDN with custom color palette (amber/emerald/rose/sky)
- HTMX-powered interactions with CSS swap animations
- Status pills, KPI cards, data tables, empty states, inline forms
- Mobile-responsive sidebar with collapsible navigation
- All existing tests updated and passing
- Zero new build dependencies — works with existing go run/air workflow

apps/go-crm/internal/handlers/customers_test.go

@@ -46,4 +46,4 @@ func TestCreateCustomerInternalSecret(t *testing.T) {
 	if w.Code != http.StatusOK && w.Code != http.StatusFound {
 		t.Fatalf("expected success with internal secret, got %d", w.Code)
 	}
-}
+}