fix(ui): replace text-default ℹ with a themed SVG info icon on the up…

CHANGELOG.md

@@ -63,6 +63,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **Upload-screen info hint shows a real info icon.** The separator-detection
+  hint led with a bare `ℹ` (U+2139), which has a text-default presentation and
+  rendered as a plain italic "i" in the mono chrome font. Replaced with an
+  inline `currentColor` SVG info mark that themes in both light and dark.
 - **Venn → UpSet handoff link no longer 404s on middle/ctrl-click.** The
   "use the UpSet tool" link pointed at `upset.html`; in the hash-routed SPA a
   new-tab open hit a non-existent page. It now targets `#/upset`.

tools/_shell/UploadPanel.tsx

@@ -336,7 +336,21 @@ function AutoDetectUploadPanel(props: UploadPanelProps) {
         }}
       >
         <div style={{ display: "flex", alignItems: "center", gap: 8 }}>
-          <span aria-hidden="true">ℹ</span>
+          {/* Inline SVG info mark (currentColor → inherits --info-text and
+              themes in both modes). Replaces a bare U+2139 "ℹ", which has a
+              text-default presentation and rendered as a plain italic "i" in
+              the mono chrome font. */}
+          <svg
+            width="15"
+            height="15"
+            viewBox="0 0 16 16"
+            aria-hidden="true"
+            style={{ flexShrink: 0 }}
+          >
+            <circle cx="8" cy="8" r="7" fill="none" stroke="currentColor" strokeWidth="1.4" />
+            <circle cx="8" cy="4.6" r="1" fill="currentColor" />
+            <rect x="7.15" y="6.8" width="1.7" height="5" rx="0.85" fill="currentColor" />
+          </svg>
           <span>
             Plöttr auto-detects the column separator (comma, tab, semicolon, …) from the data.
           </span>