feat: adopt per-bot account api key for gateway attribution and improve post distinctness

- Add `account_api_key` field to `BotState` and `_adopt_account_api_key()` method that fetches the bot's own `users.api_key` from its profile JSON after auth, switching `LLMClient` to use it instead of the shared bootstrap key, routing gateway spend through the bot's user identity
- Replace `interleave_by_author` with a simpler greedy algorithm that picks the first row whose owner differs from the last picked, removing the multi-queue priority logic
- Extend `_ai_quota` response with `unlimited`, `requests`, and `last_used` fields sourced from new `user_spend_24h()` analytics helper
- Pass `recent_post_titles` from `BotState` into `LLMClient.generate_post()` and add a `distinct_rule` prompt instructing the model to avoid repeating framing, examples, or opinions from the bot's last six posts
- Remove early-return dedup check in `ArticleRegistry.admit` that skipped articles already held by the same bot owner, allowing re-admission under a different category
- Render bot username as a clickable link with avatar in the admin bots table

devplacepy/services/openai_gateway/analytics.py

@@ -453,6 +453,29 @@ def _user_hourly(rows: list[dict]) -> list[dict]:
     return out
 
 
+def user_spend_24h(owner_id: str, hours: int = 24) -> dict:
+    hours = max(1, min(hours, MAX_WINDOW_HOURS))
+    zero = {"requests": 0, "spent_usd": 0.0, "last_used": None}
+    if not owner_id or GATEWAY_LEDGER not in db.tables:
+        return zero
+    cutoff = _iso(_now() - timedelta(hours=hours))
+    rows = list(
+        db.query(
+            f"SELECT COUNT(*) AS requests, COALESCE(SUM(cost_usd), 0) AS spent, "
+            f"MAX(created_at) AS last_used FROM {GATEWAY_LEDGER} "
+            "WHERE owner_id = :oid AND created_at >= :cutoff",
+            oid=owner_id,
+            cutoff=cutoff,
+        )
+    )
+    row = rows[0] if rows else {}
+    return {
+        "requests": int(row.get("requests") or 0),
+        "spent_usd": float(row.get("spent") or 0.0),
+        "last_used": row.get("last_used"),
+    }
+
+
 def build_user_usage(
     owner_id: str, hours: int = 24, pricing: Optional[Pricing] = None
 ) -> dict: