Add ASCII logo, spinner during install, all packages core, fix tests

- ASCII art logo on website hero and OAuth callback page
- Clean spinner during postinstall instead of npm noise
- pi-session-search and pi-memory moved to core (13 packages)
- pi-generative-ui is the only optional package
- Alpha Hub callback page branded with Feynman logo

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

.feynman/settings.json

@@ -9,7 +9,9 @@
     "npm:pi-mermaid",
     "npm:@aliou/pi-processes",
     "npm:pi-zotero",
+    "npm:@kaiserlich-dev/pi-session-search",
     "npm:pi-schedule-prompt",
+    "npm:@samfp/pi-memory",
     "npm:@tmustier/pi-ralph-wiggum"
   ],
   "quietStartup": true,