feat(brand): add Recl∆Im lockup + mark as standalone SVG assets

Two scalable artefacts under assets/branding/ so the brand can
travel outside the Flutter app — favicon source, slide footers,
press kit, GitHub social-preview, README hero. Both files use
prefers-color-scheme so a single asset inverts cleanly on
ink/paper backdrops, with the petrol signal (#2E8F9E) staying
constant on the ∆-eye and the ∆I letters in the wordmark.

  reclaim-lockup.svg — 720×200 viewBox, mark on the left, the
                       wordmark 'Recl∆Im' on the right, ∆I in
                       petrol. The single artefact a stage or
                       browser tab wants to show.

  reclaim-mark.svg   — 160×160 viewBox, just the triangle and
                       the eye. Favicon source, social cards,
                       any tight-box context.

Signed-off-by: flemming-it <sf@flemming.it>

assets/branding/reclaim-mark.svg

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Recl∆Im — standalone mark (just the ∆ + eye).
+  Use as favicon source, social-share preview, and any context where
+  the wordmark would be too wide.
+-->
+<svg xmlns="http://www.w3.org/2000/svg"
+     viewBox="0 0 160 160"
+     role="img"
+     aria-label="Recl∆Im — Mark">
+  <defs>
+    <style>
+      .signal { fill: #2E8F9E; }
+      @media (prefers-color-scheme: dark) {
+        .auto-stroke { stroke: #F4F3EF; }
+      }
+      @media (prefers-color-scheme: light) {
+        .auto-stroke { stroke: #08090A; }
+      }
+    </style>
+  </defs>
+  <polygon class="auto-stroke"
+           points="80,12 148,148 12,148"
+           fill="none"
+           stroke-width="6"
+           stroke-linejoin="miter" />
+  <circle class="signal" cx="80" cy="110" r="10" />
+</svg>