chore: keep generated images inside the project as real directories

The absolute-path + symlink layout added earlier today is awkward to
redeploy against: after a fresh clone the symlinks point at nothing and
compose quietly creates empty directories in their place, so the service
comes up healthy with no history.

/root/apps/ holds services only, so the images and the SQLite database
live in the project again as ./output and ./data, bind-mounted with
relative paths. Backups are handled by a separate hook that copies to
/root/backup_files/ai-image/, which is not part of /root/apps/.

Both directories stay gitignored.

.gitignore

@@ -3,14 +3,12 @@
 .env.*
 !.env.example
 
-# Local runtime data (SQLite + 加密密钥)
-# 2026-11-04 起真身已迁到 /root/apps/ai-image-data/（git 工作树外）。
-# 这里的 data/ output/ 只保留为指向新位置的符号链接（方便老路径继续用）。
+# Local runtime data (SQLite + 加密密钥) 与生成图片
+# 这两个是本服务的真身目录，不进 git。
+# 备份由 ruantang profile 的 backup-ai-image-output.sh 负责，
+# 落到 /root/backup_files/ai-image/。
 data/
 output/
-# 符号链接本身也别提交（目录形式的规则匹配不到 symlink）
-/data
-/output
 .screenshots/
 .trae-html-share-packages/