feat: kill conversations on off-platform and seller pushes

Seller detection on replies was a case-insensitive substring match over the
configured keyword list, and every hit landed in `human-required` alongside
genuine prospects that need a person. Off-platform pushes were only checked
for r4r policy modes, as were the under-18 signals.

Three layers now:

- New `off-platform-signals` module matches on normalized text (unicode
  folding, zero-width stripping, leet mapping, separator removal), so
  `0nlyf4ns`, `t3l3gr4m` and `t e l e g r a m` are caught. Ambiguous terms
  need context: `snap` on its own stays a photo request, never a kill.
- New terminal `killed` automation status. It records the evidence, sets the
  durable seller flag, supersedes the pending claim, and resolves triage to
  `done`, so killed conversations leave every actionable queue. Off-platform
  kills are independent of `reddit.filterSellers`.
- Optional AI screening of inbound replies behind
  `conversations.aiReplyScreening` (off by default). Runs only after the
  deterministic gates pass, memoizes per inbound event, and fails open.

Under-18 and in-person/contact-detail signals now apply to every policy mode
rather than r4r only, and remain human handoffs rather than kills.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/configuration.md

@@ -33,12 +33,19 @@ Never document real values. `.env` is ignored and may contain production credent
 - `pollIntervalMs`: legacy/scheduled polling cadence.
 - `userAgent`: Reddit JSON request identifier.
 - `targetGenders`: allowed parsed values.
-- `filterSellers`, `sellerKeywords`, `sellerDomains`: seller policy inputs. The defaults treat Telegram references, including `t.me` and `telegram.me` links, as seller signals alongside paid-content platforms and payment prompts.
+- `filterSellers`, `sellerKeywords`, `sellerDomains`: seller policy inputs; see also the `conversations` section, whose off-platform kill is independent of this flag. The defaults treat Telegram references, including `t.me` and `telegram.me` links, as seller signals alongside paid-content platforms and payment prompts.
 - `prioritizeRecentPosts`, `recentWindowMinutes`: recency/fallback behavior.
 - `maxReadyCandidates`: hard ceiling for the active candidate target; valid range 1–500. Runtime lowers the actual target to what authenticated running accounts can send within `recentWindowMinutes` under current rolling-hour and message-spacing limits.
 
 Subreddit `type` is `image` or `chat`. Conversation policy contains `mode`, `maxAutomatedTurns`, and `rapportTurnsBeforeMediaAsk`; hybrid rapport turns must be lower than the maximum.
 
+### `conversations`
+
+- `offPlatformKill` (default `true`): end a conversation outright when the reply pushes it to another app, to contact details, or to a payment rail. Independent of `reddit.filterSellers`.
+- `killOnSellerKeyword` (default `true`): a configured seller keyword or domain also ends the conversation. Set `false` to hand those to an operator instead.
+- `aiReplyScreening.enabled` (default `false`): second-stage classifier on inbound replies, run only when the deterministic rules pass. Uses `openrouter.chatModel` and its fallbacks, and fails open.
+- `aiReplyScreening.killConfidence` (default `0.8`) / `flagConfidence` (default `0.6`): thresholds at which a seller/off-platform/scam/bot verdict kills or hands off.
+
 ### `openrouter`
 
 Contains image/chat primary and fallback models plus the analysis, message, and chat-opener prompt templates. The API key is environment-only. Model fallback and prompt changes affect cost, behavior, and experiment attribution and need focused tests plus operator-visible metadata.