Review fixes: swipe (capture-phase, enabled in TG), TG header aligns to the nav band, DnD zoom delay 1s->0.7s

- Edge-swipe back now listens at the window in the CAPTURE phase (the board's
  pointer handlers can't swallow it) and is no longer skipped inside Telegram
  (where the owner tests it).
- TG-fullscreen header: expose the device safe-area top (--tg-safe-top) and
  centre the title + menu pair within Telegram's nav band ([safe-top,
  content-top]) below the notch, keeping the band's height — lining up with
  Telegram's own controls.
- DnD auto-zoom-on-hover delay reduced 1000ms -> 700ms.

(Client-IP: diagnosed as the owner's home-router SNAT — the host caddy already
receives 192.168.0.1 with no XFF, so the real IP is lost upstream of our stack;
correct in prod. No code change.)

ui/src/components/Screen.svelte

@@ -3,7 +3,6 @@
   import Header from './Header.svelte';
   import AdBanner from './AdBanner.svelte';
   import { navigate } from '../lib/router.svelte';
-  import { insideTelegram } from '../lib/telegram';
 
   // The app-shell layout (all screens): the nav bar grows; the ad strip, content and
   // optional tab bar pin to the bottom (ad directly above the content). Pass `scroll`
@@ -37,25 +36,28 @@
   const SHOW_AD_BANNER = false;
 
   // Edge-swipe back (Stage 17): a left-edge rightward drag returns to `back`, the standard
-  // mobile gesture. Armed only from the very left edge (<=24px) so it never competes with the
-  // board's own horizontal gestures; touch/pen only. Skipped inside Telegram, whose native
-  // back button + swipe already cover this (and would otherwise double up).
-  function onEdgeDown(e: PointerEvent): void {
-    if (!back || e.pointerType === 'mouse' || insideTelegram() || e.clientX > 24) return;
-    const x0 = e.clientX;
-    const y0 = e.clientY;
-    const onUp = (ev: PointerEvent) => {
-      window.removeEventListener('pointerup', onUp);
-      const dx = ev.clientX - x0;
-      const dy = ev.clientY - y0;
-      if (back && dx > 64 && Math.abs(dx) > Math.abs(dy) * 1.4) navigate(back);
-    };
-    window.addEventListener('pointerup', onUp);
-  }
+  // mobile gesture. Listened at the window in the CAPTURE phase so the board's own pointer
+  // handlers (which capture/stop the event) can never swallow it; armed only from the very
+  // left edge (<=24px), touch/pen only, so it never competes with the board's gestures.
+  $effect(() => {
+    function onDown(e: PointerEvent) {
+      if (!back || e.pointerType === 'mouse' || e.clientX > 24) return;
+      const x0 = e.clientX;
+      const y0 = e.clientY;
+      const onUp = (ev: PointerEvent) => {
+        window.removeEventListener('pointerup', onUp, true);
+        const dx = ev.clientX - x0;
+        const dy = ev.clientY - y0;
+        if (back && dx > 64 && Math.abs(dx) > Math.abs(dy) * 1.4) navigate(back);
+      };
+      window.addEventListener('pointerup', onUp, true);
+    }
+    window.addEventListener('pointerdown', onDown, true);
+    return () => window.removeEventListener('pointerdown', onDown, true);
+  });
 </script>
 
-<!-- svelte-ignore a11y_no_static_element_interactions -->
-<div class="screen" onpointerdown={onEdgeDown}>
+<div class="screen">
   <Header {title} {back} {menu} grow={growNav} />
   {#if SHOW_AD_BANNER}<AdBanner />{/if}
   <main class="content" class:scroll class:fill={!growNav} class:column>{@render children?.()}</main>