ui(badges): add background image bleed support (cfg_json, PVC layout)

- Add `bleed` field to BadgeTemplateCfg (CSS length, e.g. "0.125in")
- Badge view: derive bleed_offset, move bg-image to absolute positioned div
  that extends past card edges; add isolation:isolate to badge_front stacking context
- Template form: add bleed input in Advanced > Appearance; wire to cfg_json save/load
- PVC layout CSS: change overflow:hidden → overflow:visible in print rule to allow
  bleed div to render at physical card boundary (Zebra driver clips at card edge)
- Prevents white borders on PVC cards when printer has slight alignment variance.
  Screen preview shows bleed visually extending past the card outline.

src/lib/ae_events/badges/css/badge_layout_zebra_zc10l_pvc.css

@@ -44,6 +44,8 @@
         height: 5.5in !important;
         max-width: 3.5in !important;
         max-height: 5.5in !important;
-        overflow: hidden !important;
+        /* Allow visible: the bleed div inside badge_front extends past the card
+           boundary intentionally. The Zebra driver clips at the physical card edge. */
+        overflow: visible !important;
     }
 }

src/lib/ae_events/types/ae_badge_template_cfg.ts

@@ -30,6 +30,12 @@ export interface BadgeTemplateCfg {
     // Body text color: either a Tailwind `text-*` class or a hex color like `#112233`.
     body_text_color?: string;
 
+    // Background image bleed: how far the background image extends past the physical
+    // card edge on all four sides. Prevents white borders when the printer clips at the
+    // card boundary. Any CSS length is valid: "0.125in", "3mm", "9px".
+    // Leave unset (or "0") for no bleed.
+    bleed?: string;
+
     // Allow arbitrary extra keys to preserve forward-compatibility.
     [key: string]: any;
 }