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/templates/_comment_form.html

@@ -9,14 +9,14 @@
             max-size="{{ max_upload_size_mb() }}"
             max-files="{{ max_attachments_per_resource() }}"
             allowed-types="{{ allowed_file_types() }}"></dp-upload>
-        <button type="submit" class="comment-form-submit"><span class="icon">&#x1F4E4;</span> Post</button>
+        <button type="submit" class="comment-form-submit"><span class="icon">&#x1F4E4;</span><span class="label"> Post</span></button>
     </div>
 </form>
 {% else %}
 <form class="comment-form comment-form-guest" onsubmit="return false">
     <textarea name="content" placeholder="Your opinion goes here..." disabled aria-disabled="true"></textarea>
     <div class="comment-form-actions">
-        <button type="button" class="comment-form-submit" disabled aria-disabled="true" title="Log in to participate"><span class="icon">&#x1F4E4;</span> Post</button>
+        <button type="button" class="comment-form-submit" disabled aria-disabled="true" title="Log in to participate"><span class="icon">&#x1F4E4;</span><span class="label"> Post</span></button>
         {{ login_hint(user) }}
     </div>
 </form>