Rebuild on the RealBrain design system and retarget SEO to content credentials

Search Console (Jun 4 – Sep 3) shows the page ranking on the first results
page for "content credentials" queries while converting badly: "ai
credentials remover" at 113 impressions and 0.88% CTR from position 6.7,
"remove content credentials from image online" at 2.15% from position 5.0,
"remove ai content credentials from image" at 0% from position 7.8. The
title led with "EXIF metadata", a phrase that appears in none of the top
queries, so the snippet never matched the intent behind the impressions.

SEO
- Title, description and H1 rebuilt around "remove content credentials from
  an image"; EXIF kept as a secondary term.
- Added a how-to section and a nine-question FAQ answering the question
  queries that had no content behind them, including the LinkedIn AI label
  and the Instagram AI tag.
- Structured data as an @graph: WebSite (alternateName "Untrace AI" for the
  unserved brand query), Organization, WebApplication, HowTo, FAQPage.
- Fixed sitemap.xml, which pointed at /untrace/ — a URL that does not exist.
- Regenerated the Open Graph image to match the new design.

Design
- Vendored the design system at src/tokens.css and composed the app from it.
  The old styling broke most of its rules: gradients, font weights 800 and
  900, raw #2563eb, Inter, and emoji as the only status signal.
- Reworked the tool into a Scan / Review / Download flow that lists what it
  found before changing anything, with the primary action pinned within
  thumb reach on small screens.
- Dark by default with a light theme, applied before first paint so the page
  never flashes the wrong surface.
- Replaced the floating donation widget, which painted an off-token circle
  over the page and covered the mobile action bar, with a footer link.

Structure
- Moved detection into src/lib/metadata.js and removal into src/lib/clean.js;
  the canvas callbacks are now a promise chain.
- Dropped Tailwind and PostCSS. Both were configured twice, and no Tailwind
  utility was used. Stylesheet is 6.2 kB gzipped with the whole system in it.

Fixes
- The stepper never advanced: stepState(index) read `current` from the
  closure, which Svelte 4 cannot track as a template dependency.
- The cleaner's fallback returned the original, uncleaned file while the UI
  reported "All EXIF metadata removed". It now reports the failure instead.

Verified against a JPEG carrying EXIF, GPS, XMP and an APP11 JUMBF C2PA
manifest: the output retains only APP0 and the sRGB ICC profile, with every
provenance marker gone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018pRSdR57Ze9M2meDfYZgYE

public/favicon-32x32.svg

@@ -1,27 +1,5 @@
-<svg width="32" height="32" viewBox="0 0 48 48" fill="none" xmlns="http://www.w3.org/2000/svg">
-  <!-- Medium detail version for 32x32 -->
-  <defs>
-    <linearGradient id="logoGradient32" x1="0%" y1="0%" x2="100%" y2="100%">
-      <stop offset="0%" style="stop-color:#3B82F6;stop-opacity:1" />
-      <stop offset="100%" style="stop-color:#1E40AF;stop-opacity:1" />
-    </linearGradient>
-  </defs>
-
-  <!-- Main circle background -->
-  <circle cx="24" cy="24" r="22" fill="url(#logoGradient32)" />
-
-  <!-- Image/photo icon -->
-  <rect x="11" y="15" width="26" height="18" rx="2" fill="white" opacity="0.9" />
-  <rect x="12" y="16" width="24" height="16" rx="2" fill="none" stroke="#1E40AF" stroke-width="1.5" />
-
-  <!-- Simple landscape -->
-  <path d="M12 28 L18 23 L24 26 L30 21 L36 26 V30 H12 Z" fill="#E5E7EB" opacity="0.6" />
-
-  <!-- Strike-through line -->
-  <line x1="8" y1="8" x2="40" y2="40" stroke="#EF4444" stroke-width="3" stroke-linecap="round" opacity="0.8" />
-  <line x1="8" y1="8" x2="40" y2="40" stroke="white" stroke-width="1.5" stroke-linecap="round" />
-
-  <!-- Shield -->
-  <path d="M37 12 L41 12 C41.5 12 42 12.5 42 13 L42 16 C42 18.5 40.5 20.8 38.2 22.1 L37 22.8 L35.8 22.1 C33.5 20.8 32 18.5 32 16 L32 13 C32 12.5 32.5 12 33 12 L37 12 Z" fill="#10B981" stroke="white" stroke-width="1" />
-  <path d="M35 15.5 L36.5 17 L39 14.5" stroke="white" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round" />
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" role="img" aria-label="Untrace">
+  <rect width="48" height="48" rx="10" fill="#3450C8"/>
+  <text x="24" y="24" fill="#FFFFFF" font-family="'IBM Plex Mono', ui-monospace, monospace"
+        font-size="28" font-weight="600" text-anchor="middle" dominant-baseline="central">U</text>
 </svg>