feat: add backup CLI commands, AI correction/modifier services, and timezone-aware date display

- Add `devplace backups` CLI subcommands (list, run, prune, clear) with job enqueueing and orphan cleanup
- Introduce `BACKUPS_DIR` and `BACKUP_STAGING_DIR` config paths for backup storage
- Implement `schedule_correction` and `schedule_modification` calls in content creation, comment creation, and comment editing flows
- Add `DEFAULT_CORRECTION_PROMPT` and `DEFAULT_MODIFIER_PROMPT` config constants for AI content processing
- Document timezone-aware date display using `local_dt`/`dt_ago` Jinja globals with client-side `Intl` localization
- Update README with AI content correction/modifier support in direct messages via `@ai` inline instructions
- Add `track_action(user["uid"], "vote")` call on upvote in `apply_vote`

devplacepy/config.py

@@ -24,6 +24,8 @@ CONTAINER_WORKSPACES_DIR = DATA_DIR / "container_workspaces"
 ZIPS_DIR = DATA_DIR / "zips"
 ZIP_STAGING_DIR = DATA_DIR / "zip_staging"
 FORK_STAGING_DIR = DATA_DIR / "fork_staging"
+BACKUPS_DIR = DATA_DIR / "backups"
+BACKUP_STAGING_DIR = DATA_DIR / "backup_staging"
 SEO_REPORTS_DIR = DATA_DIR / "seo_reports"
 PLANNING_REPORTS_DIR = DATA_DIR / "planning_reports"
 DBAPI_DIR = DATA_DIR / "dbapi"
@@ -72,6 +74,10 @@ INTERNAL_GATEWAY_URL = f"{INTERNAL_BASE_URL}/openai/v1/chat/completions"
 INTERNAL_EMBED_URL = f"{INTERNAL_BASE_URL}/openai/v1/embeddings"
 INTERNAL_MODEL = "molodetz"
 INTERNAL_EMBED_MODEL = "molodetz~embed"
+DEFAULT_CORRECTION_PROMPT = "Leave literary as is, only do punctuation and casing"
+DEFAULT_MODIFIER_PROMPT = (
+    "Execute what is behind `@ai` (the prompt) and replace that part including `@ai`"
+)
 
 SERVICE_LOCK_FILE = LOCKS_DIR / "devplace-services.lock"
 INIT_LOCK_FILE = LOCKS_DIR / "devplace-init.lock"
@@ -103,6 +109,8 @@ DATA_PATHS: dict[str, Path] = {
     "zips": ZIPS_DIR,
     "zip_staging": ZIP_STAGING_DIR,
     "fork_staging": FORK_STAGING_DIR,
+    "backups": BACKUPS_DIR,
+    "backup_staging": BACKUP_STAGING_DIR,
     "seo_reports": SEO_REPORTS_DIR,
     "planning_reports": PLANNING_REPORTS_DIR,
     "dbapi": DBAPI_DIR,