Use the original iPodderX icon instead of a placeholder

Recovered from the Internet Archive's capture of ipodderx.com: the icon
was never in either repo, since only the Python engine was open-sourced
and the .icns lived in the Cocoa bundle. Kept as a file in web/ and
embedded as a data URI for the sidebar mark and the favicon.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RPyeapneuXrCdojsaiXGbe

PROGRESS.md

@@ -56,6 +56,26 @@ and until now nothing set them.
 
 ---
 
+## 2026-09-10 — The real iPodderX icon
+
+The sidebar mark was an invented `ix` placeholder. The original icon is not in this repo or the
+legacy one: only the Python engine was open-sourced, never the Cocoa bundle whose Resources held the
+`.icns` (the legacy repo's history contains nothing but .py/.so/.po/.mo/LICENSE/README).
+
+Recovered from the Internet Archive's capture of ipodderx.com: `_graphics/iPXicon.jpg`, 173x165 --
+the white iPod-style device with the antenna and EQ display. That is the largest surviving copy; the
+site's 2005 `favicon.ico` is far too small to use. Saved as `web/ipodderx-icon.jpg` so the file lives
+in the tree, and embedded as a base64 data URI (12.7 KB) for both the sidebar mark and the favicon,
+which avoids an extra asset route.
+
+`.logo` changed from a gradient chip to a white rounded tile, since the icon is photo-style on a
+light ground.
+
+Provenance is Ray's own: the app was Slakinski & Trometer / Thunderstone Media, and this is its
+successor.
+
+---
+
 ## 2026-09-10 — Feed URL is editable, with a copy button
 
 The URL in a feed's Settings is now an editable field paired with Copy. Entries and download