chore(dev): finish --watch → --hot sweep across remaining Bun services

Catches the service-level package.json files that the previous
sweep (4cca25ed0) missed — they don't appear in any dev:*:full
orchestrator but get invoked when someone runs `pnpm --filter
@mana/<service> dev` directly.

Touched: mana-geocoding, mana-mail, mana-subscriptions, mana-mcp,
news-ingester, mana-persona-runner, mana-research, mana-user,
plus apps/memoro (server + audio-server).

mana-ai stays on --watch on purpose: its entry uses an explicit
`Bun.serve({...})` call instead of `export default { port,
fetch }`, plus a SIGTERM/SIGINT handler that calls
`server.stop()`. --hot would replace the module without releasing
the old server reference and produce exactly the EADDRINUSE we're
trying to avoid. If mana-ai gets refactored to the standard
default-export shape, flip its dev script too.

services/mana-research/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",
 		"test": "bun test",
 		"db:push": "drizzle-kit push",