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

tests/unit/services/devii/config.py

@@ -26,6 +26,18 @@ def _seed_ledger(owner_kind, owner_id, cost, n=1):
                 "cost_usd": cost,
             }
         )
+def _seed_gateway_spend(owner_id, cost, n=1, owner_kind="user"):
+    table = get_table("gateway_usage_ledger")
+    for _ in range(n):
+        table.insert(
+            {
+                "owner_kind": owner_kind,
+                "owner_id": owner_id,
+                "created_at": _now_iso_devii_quota(),
+                "success": 1,
+                "cost_usd": cost,
+            }
+        )
 def _ensure_devii():
     from devplacepy.services.manager import service_manager
     from devplacepy.services.devii import DeviiService
@@ -70,11 +82,13 @@ def test_admin_exempt_by_default(local_db):
     set_setting("devii_admin_daily_usd", "0.0")
     try:
         uid, _ = _make_user_devii_quota()
-        _seed_ledger("user", uid, 5.0)
+        _seed_gateway_spend(uid, 5.0)
         member_view = _ai_quota(uid, is_admin=False)
         admin_view = _ai_quota(uid, is_admin=True)
         assert member_view["used_pct"] == 100.0
+        assert member_view["unlimited"] is False
         assert admin_view["used_pct"] == 0.0
+        assert admin_view["unlimited"] is True
     finally:
         set_setting("devii_user_daily_usd", "1.0")
         set_setting("devii_admin_daily_usd", "0.0")
@@ -97,7 +111,7 @@ def test_admin_cap_configurable(local_db):
     set_setting("devii_admin_daily_usd", "2.0")
     try:
         uid, _ = _make_user_devii_quota()
-        _seed_ledger("user", uid, 1.0)
+        _seed_gateway_spend(uid, 1.0)
         quota = _ai_quota(uid, is_admin=True)
         assert quota["used_pct"] == 50.0
     finally: