chore(dev): switch all Bun services from --watch to --hot

Fans out the cards-server fix from 08f422340 to every other Bun
service in the monorepo. --hot keeps the port bound across HMR
reloads via globalThis[hmrSymbol]; --watch restarts the process
and races old/new Bun.serve for the port.

Touched: dev:auth, dev:credits, dev:events, dev:analytics,
dev:memoro:server, dev:memoro:audio-server, dev:uload:server in
the root package.json plus the matching `dev` script in each
service's own package.json. All six services already export the
`{ port, fetch }` default that Bun's --hot expects.

Smoke-tested: pnpm dev:cardecky:full boots clean, then touching
auth/credits/cards-server entry files all hot-reload without
dropping their port.

(memoro/apps/audio-server doesn't have a `dev: bun --watch ...`
script in its own package.json, so only the root entry got the
swap there.)

apps/uload/apps/server/package.json

@@ -4,7 +4,7 @@
 	"private": true,
 	"type": "module",
 	"scripts": {
-		"dev": "bun run --watch src/index.ts",
+		"dev": "bun run --hot src/index.ts",
 		"start": "bun run src/index.ts",
 		"type-check": "tsc --noEmit"
 	},