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/static/css/engagement.css

@@ -13,6 +13,10 @@
     gap: var(--space-sm);
 }
 
+.reaction-list:not(:has(.reaction-chip:not([hidden]))) {
+    display: none;
+}
+
 .reaction-chip {
     display: inline-flex;
     align-items: center;
@@ -59,25 +63,28 @@
 .reaction-add-btn {
     display: inline-flex;
     align-items: center;
-    gap: var(--space-xs);
-    padding: 0.15rem 0.6rem;
-    border: 1px dashed var(--border-light);
-    border-radius: 999px;
-    background: transparent;
+    gap: 0.375rem;
+    padding: 0.375rem 0.75rem;
+    border: none;
+    border-radius: var(--radius);
+    background: none;
     color: var(--text-muted);
-    font-size: 0.85rem;
-    line-height: 1.4;
+    font-size: 0.8125rem;
+    font-weight: 500;
+    line-height: 1;
     cursor: pointer;
-    transition: border-color 0.15s, color 0.15s;
+    transition: color 0.15s;
 }
 
 .reaction-add-btn:hover {
     color: var(--accent);
-    border-color: var(--accent);
 }
 
 .reaction-add-icon {
     font-size: 1rem;
+    width: 20px;
+    text-align: center;
+    flex-shrink: 0;
     line-height: 1;
 }
 
@@ -103,6 +110,14 @@
     display: none;
 }
 
+@media (max-width: 768px) {
+    .reaction-palette {
+        flex-wrap: wrap;
+        justify-content: flex-start;
+        max-width: calc(100vw - 2 * var(--space-md));
+    }
+}
+
 .reaction-palette-btn {
     background: transparent;
     border: none;