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

src/lib/Dropzone.svelte

@@ -0,0 +1,130 @@
+<script>
+  import { createEventDispatcher } from "svelte";
+  import { ACCEPTED_EXTENSIONS, isAccepted } from "./metadata.js";
+  import Icon from "./Icon.svelte";
+
+  const dispatch = createEventDispatcher();
+
+  export let busy = false;
+
+  let dragging = false;
+  let fileInput;
+  let depth = 0;
+
+  function offer(file) {
+    if (!file) return;
+    if (!isAccepted(file)) {
+      dispatch("reject", {
+        message: `Untrace cannot read ${file.type || "that file type"}. Choose a JPEG, PNG, TIFF, HEIC or AVIF image.`,
+      });
+      return;
+    }
+    dispatch("select", { file });
+  }
+
+  function onDrop(event) {
+    event.preventDefault();
+    depth = 0;
+    dragging = false;
+    if (busy) return;
+    offer(event.dataTransfer?.files?.[0]);
+  }
+
+  function onDragEnter(event) {
+    event.preventDefault();
+    if (busy) return;
+    depth += 1;
+    dragging = true;
+  }
+
+  function onDragLeave(event) {
+    event.preventDefault();
+    depth = Math.max(0, depth - 1);
+    if (depth === 0) dragging = false;
+  }
+
+  function onChange(event) {
+    offer(event.target.files?.[0]);
+    // Reset so choosing the same file twice still fires a change event.
+    event.target.value = "";
+  }
+
+  function onPaste(event) {
+    if (busy) return;
+    const item = [...(event.clipboardData?.items || [])].find((entry) =>
+      entry.type.startsWith("image/")
+    );
+    if (item) offer(item.getAsFile());
+  }
+</script>
+
+<svelte:window
+  on:paste={onPaste}
+  on:dragover|preventDefault
+  on:drop|preventDefault
+/>
+
+<button
+  type="button"
+  class="dropzone"
+  data-drag={dragging}
+  disabled={busy}
+  on:click={() => fileInput.click()}
+  on:dragenter={onDragEnter}
+  on:dragover|preventDefault
+  on:dragleave={onDragLeave}
+  on:drop={onDrop}
+>
+  <span class="glyph"><Icon name="upload" size="lg" /></span>
+  <span class="title">
+    {dragging ? "Drop to scan it" : "Drop an image, or choose a file"}
+  </span>
+  <span class="hint">
+    Nothing is uploaded. The image is read and rewritten inside this tab.
+  </span>
+  <span class="chip-row formats">
+    <span class="chip">JPEG</span>
+    <span class="chip">PNG</span>
+    <span class="chip">TIFF</span>
+    <span class="chip">HEIC</span>
+    <span class="chip">AVIF</span>
+  </span>
+</button>
+
+<p class="paste-hint">
+  You can also paste an image with <kbd>Ctrl</kbd>+<kbd>V</kbd>.
+</p>
+
+<input
+  class="visually-hidden"
+  type="file"
+  accept={ACCEPTED_EXTENSIONS}
+  bind:this={fileInput}
+  on:change={onChange}
+  tabindex="-1"
+  aria-hidden="true"
+/>
+
+<style>
+  .formats {
+    justify-content: center;
+    margin-top: var(--space-2);
+  }
+
+  .paste-hint {
+    margin-top: var(--space-3);
+    text-align: center;
+    color: var(--text-3);
+    font-size: var(--fs-1);
+    line-height: var(--lh-1);
+  }
+
+  kbd {
+    font-family: var(--font-mono);
+    font-size: var(--fs-1);
+    color: var(--text-2);
+    padding: 0 var(--space-1);
+    border: var(--border-w) solid var(--border-strong);
+    border-radius: var(--radius-sm);
+  }
+</style>