deepdive: add Beat-5 'Everything Client-Managed' frame around platform stack

Why: closes the Beat-5 summary with a visible boundary + label so the
"client-managed" point lands visually, not just in copy.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

protected/deepdive.html

@@ -226,6 +226,9 @@
             <p class="pl-body">
               Fenja brings together all the pieces to solve simple
               and complex AI use cases across your organisation.
+              Every component hosted in your infrastructure with
+              full traceability and governance. Secure and sovereign
+              by design.
             </p>
           </div>
 
@@ -238,6 +241,13 @@
         <div class="pl-canvas-wrap">
           <div class="pl-canvas">
 
+            <!-- Beat-5 frame: thin border around all three layers
+                 with a top-right label. Hidden until Beat 5 fires;
+                 platform.js fades opacity to 1. -->
+            <div class="pl-canvas-frame" aria-hidden="true">
+              <span class="pl-canvas-frame-label">Everything Client-Managed</span>
+            </div>
+
             <!-- Foundation — 3 equal cards (corrects the original
                  handoff's tall-Knowledge asymmetry: that asymmetry
                  was for a single Knowledge concept; we've split

protected/platform.css

@@ -318,11 +318,40 @@ body:has(#page-product-deepdive.is-active) .dot-nav-tray { opacity: 0; }
 }
 
 .pl-canvas {
+  position: relative;    /* anchors .pl-canvas-frame */
   display: flex;
   flex-direction: column;
   gap: 20px;             /* layer-to-layer gap, per design spec */
 }
 
+/* Beat-5 frame — a thin outline around the three settled layer
+   groups with a label sitting above the top-right corner. Initial
+   opacity 0 so it's invisible during Beats 1–4; platform.js fades
+   it in on Beat 5. The negative inset gives breathing room between
+   the existing card-group surfaces and the outline. */
+.pl-canvas-frame {
+  position: absolute;
+  inset: -18px;
+  border: 1px solid var(--outline-variant, rgba(56,56,49,0.22));
+  border-radius: calc(var(--radius-lg) + 6px);
+  pointer-events: none;
+  opacity: 0;
+}
+
+.pl-canvas-frame-label {
+  position: absolute;
+  bottom: 100%;          /* sits above the top edge */
+  right: 0;
+  margin-bottom: 8px;
+  font-family: var(--font-sans);
+  font-size: 11px;
+  font-weight: 600;
+  letter-spacing: 0.14em;
+  text-transform: uppercase;
+  color: var(--on-surface-variant);
+  white-space: nowrap;
+}
+
 .pl-eyebrow {
   font-family: var(--font-sans);
   font-weight: 500;
@@ -475,4 +504,5 @@ body:has(#page-product-deepdive.is-active) .dot-nav-tray { opacity: 0; }
   #platform-layers .pl-canvas-wrap { width: 100%; }
   #platform-layers .pl-group { opacity: 1; }
   #platform-layers .pl-card  { opacity: 1; transform: none; }
+  #platform-layers .pl-canvas-frame { opacity: 1; }
 }

protected/platform.js

@@ -125,6 +125,7 @@
     const cardsF      = groupF ? Array.from(groupF.querySelectorAll('.pl-card')) : [];
     const cardsT      = groupT ? Array.from(groupT.querySelectorAll('.pl-card')) : [];
     const cardsA      = groupA ? Array.from(groupA.querySelectorAll('.pl-card')) : [];
+    const frame       = section.querySelector('.pl-canvas-frame');
 
     if (!groupF || !groupT || !groupA ||
         copies.length !== 5 ||
@@ -145,6 +146,7 @@
     gsap.set([groupF, groupT, groupA], { opacity: 0 });
     gsap.set([...cardsF, ...cardsT, ...cardsA], { opacity: 0, y: 24 });
     gsap.set(copies, { opacity: 0, y: 14 });
+    if (frame) gsap.set(frame, { opacity: 0 });
 
     const BEAT = 1.0;
     const tl = gsap.timeline({
@@ -212,10 +214,12 @@
     fadeInCopy(3, t4);
 
     // Beat 5 — closing summary panel. Diagram is fully assembled
-    // by now; only the copy stage swaps to the summary text.
+    // by now; the copy stage swaps to the summary text and the
+    // "Everything Client-Managed" frame fades in around the stack.
     const t5 = 4 * BEAT;
     fadeOutPrev(4, t5);
     fadeInCopy(4, t5);
+    if (frame) tl.to(frame, { opacity: 1, duration: 0.20, ease: 'power2.out' }, t5 + 0.10);
   }
 
   // ─── "The Platform" Part A: The Question ────────────────────