feat: replace blinko with affine, route notifications to telegram

- Add AFFiNE stack (affine.pivoine.art): main app, migration job,
  redis, pgvector postgres
- Remove blinko stack
- Update backup.sh: swap blinko_db → affine_db
- Update README

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

affine/.env.example

@@ -0,0 +1,5 @@
+TRAEFIK_HOST=affine.example.com
+NETWORK_NAME=falcon_network
+DB_USERNAME=affine
+DB_PASSWORD=change_me
+DB_DATABASE=affine