Bsky link card service (#4547)

* setup bskycard

* quick proof of concept for png card generation

* bskycard: use jsx

* bskycard: 3x5 profile layout

* bskycard: add butterfly overlay

* bskycard: tidy

* bskycard: separate and reorganize

* bskycard: tidy

* bskycard: tidy

* bskycard: tidy

* bskycard: poc of transparent overlay and box shadow

* bskycard: reorg impl into src/ directory

* bskycard: use more standard app structure

* bskycard: setup dockerfile, fix build

* bskycard: support for x-origin-verify

* bskycard: card layout, filter images based on labels

* bskycard: tidy

* bskycard: support cluster mode

* bskycard: handle error fetching starter pack info

* bskycard: tidy

* bskycard: fix leak on failed image fetch

* bskycard: build workflow

* bskyogcard: rename from bskycard

* bskyogcard: fix some express plumbing

* bskyogcard: add cdn tags, tidy

bskyogcard/src/routes/index.ts

@@ -0,0 +1,13 @@
+import {Express} from 'express'
+
+import {AppContext} from '../context.js'
+import {default as health} from './health.js'
+import {default as starterPack} from './starter-pack.js'
+
+export * from './util.js'
+
+export default function (ctx: AppContext, app: Express) {
+  app = health(ctx, app) // GET /_health
+  app = starterPack(ctx, app) // GET /start/:actor/:rkey
+  return app
+}