chore: extract ShareServer into its own repository

Move the existing Hono API, React console, tests, build configuration,
and feature documentation from GoodBuddy into a standalone project.
Keep the current interactive-prototype behavior and production limitations.

Document the source commit and sibling-checkout links to the authoritative
Desktop network architecture. Independent install, tests, typecheck, lint,
build, and built-service HTTP smoke checks passed.

server/index.ts

@@ -0,0 +1,9 @@
+import { serve } from '@hono/node-server'
+import { app } from './app.js'
+
+const port = Number(process.env.SHARESERVER_PORT ?? 8787)
+const hostname = process.env.SHARESERVER_HOST ?? '127.0.0.1'
+
+serve({ fetch: app.fetch, port, hostname }, (info) => {
+  console.log(`ShareServer interactive prototype listening on http://${hostname}:${info.port}`)
+})