Bsky short link service (#4542)

* bskylink: scaffold service w/ initial config and schema

* bskylink: implement link creation and redirects

* bskylink: tidy

* bskylink: tests

* bskylink: tidy, add error handler

* bskylink: add dockerfile

* bskylink: add build

* bskylink: fix some express plumbing

* bskyweb: proxy fallthrough routes to link service redirects

* bskyweb: build w/ link proxy

* Add AASA to bskylink (#4588)

---------

Co-authored-by: Hailey <me@haileyok.com>

bskylink/src/routes/siteAssociation.ts

@@ -0,0 +1,13 @@
+import {Express} from 'express'
+
+import {AppContext} from '../context.js'
+
+export default function (ctx: AppContext, app: Express) {
+  return app.get('/.well-known/apple-app-site-association', (req, res) => {
+    res.json({
+      appclips: {
+        apps: ['B3LX46C5HS.xyz.blueskyweb.app.AppClip'],
+      },
+    })
+  })
+}