feat: rebrand to website design, Apple HIG icons, ASCII onboarding animation

- Align Electron CSS with website design schema (Inter font, #FBFAF5/#191919
  palette, #213448/#94B4C1 accent)
- Generate proper app icons from logo.svg via cairosvg (no more Pillow ladder)
- Square bg icons for Electron/tray (Apple HIG — OS applies squircle mask)
- Circle bg icons for website favicon only
- Add scrolling ASCII agent-activity animation to onboarding hero left panel
- Remove dock.setIcon() — let macOS use bundle .icns with system mask
- Fix goal title overflow with min-w-0 for flex truncation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/renderer/main.tsx

@@ -1,4 +1,6 @@
+import "@fontsource-variable/inter";
 import "@fontsource-variable/jetbrains-mono";
+import "@fontsource/instrument-serif";
 import "./styles.css";
 import { StrictMode } from "react";
 import { createRoot } from "react-dom/client";