New STALE_DONOR_ALERT_DAYS (.env, global threshold, 0=off) + per-route
stale_alert_enabled/stale_alert_ids (routes.json). Checked once per route
per cycle against MAX(posted_at) in the DB - self-resetting via a single
route_alerts.stale_alert_sent_at timestamp compared against the last post
time, so it fires once per quiet spell and re-arms automatically once the
donor posts again, no separate ack/clear step needed.
If a configured stale_alert_ids recipient can't be reached (never started
a chat with the bot), the global TG_ADMIN_IDS get a separate notice about
that delivery failure instead of the alert silently vanishing.
Posts can now be sourced from multiple VK groups, each routed to its own
Telegram/MAX destination(s) with independent on/off switches, configured
via data/routes.json (supports // line comments). Falls back to a single
route auto-generated from the legacy VK_SOURCE/TG_CHAT_ID/MAX_CHAT_ID env
vars if routes.json doesn't exist yet, so existing deployments keep working.
Routes are processed strictly sequentially within a cycle (no concurrency)
to keep flood control on VK/TG/MAX correct, since bot tokens are shared
across routes. DB schema gains route_id in the posts uniqueness key so the
same VK donor can safely feed multiple routes without status collisions.
Also removes the trailing-hashtag-stripping logic in text_formatter, which
was silently deleting VK posts' own hashtags whenever COMMON_TAGS wasn't
configured (it always wasn't) - posts are now forwarded unchanged.
exostring