New logo: diagonal transfer arrows + lock (SVG-first icon pipeline)

Glyph composed from mynaui arrow-diagonal-one (both diagonals) with the
mini-lock of lock-square centered between them — the macOS squircle plays the
role of lock-square's outer square. Indigo gradient + white strokes + amber
lock face for the app icon; a pure black+alpha variant for the macOS template
tray icon, plus 21 pre-rendered tray progress frames (faded arrows + fill bar,
0-100% in 5% steps) for the upcoming tray feature.

Pipeline: scripts/gen-icons.ts renders every size directly from the SVGs with
@resvg/resvg-js (dev-only dep, prebuilt binaries, no postinstall); replaces
make-icon.py + gen-iconset.sh and the sips/iconutil path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -112,10 +112,11 @@ export const BRANDING = {
 } as const;
 ```
 
-To change the icon: replace `assets/icon.png` (1024×1024) and run
-`./scripts/gen-iconset.sh` (regenerates the `.iconset` with `sips`), or point
-`icon` at your own `.iconset`. `scripts/make-icon.py` regenerates the current
-placeholder.
+To change the icon: edit `assets/logo.svg` (app icon) and
+`assets/tray/tray-glyph.svg` (menu-bar glyph), then run
+`bun scripts/gen-icons.ts` — it regenerates the macOS iconset, `icon.png`, the
+tray template image, and the tray progress frames from the SVGs
+(`@resvg/resvg-js`, dev-only dependency).
 
 > Renaming `appName` changes the app-data directory, so existing saved
 > connections won't be found under the new name — copy `connections.json` across