fix(moderation): remove manual reanalyze triggers — auto-recovery only

Manual per-message and batch reanalyze buttons/endpoints let anyone
re-queue arbitrary messages for LLM analysis, burning AI credits on
spam. Removed:
- FE: Reanalyze buttons in message list, search panel, and messages page
- FE: useReanalyze/useReanalyzeBatch hooks + messagesApi methods
- BE: POST /api/messages/:id/reanalyze and /reanalyze-batch endpoints
- BE: markForReanalysis/reanalyzeErrorBatch service+repository methods

Recovery of failed messages is fully automatic: the discord-gateway
startPendingAIAnalysisWorker retries 'pending' (batch path) and
'error/analysis_incomplete' (individual path) messages on
AI_ANALYSIS_RECOVERY_INTERVAL_MS.

services/backend/src/modules/messages/messages.service.ts

@@ -58,15 +58,6 @@ export class MessagesService {
     return messagesRepository.getImageMessages(guildId, limit);
   }
 
-  async markForReanalysis(id: string): Promise<void> {
-    if (!id) {
-      throw new ValidationError("message ID is required");
-    }
-
-    logger.debug({ id }, "Marking message for re-analysis");
-    await messagesRepository.markForReanalysis(id);
-  }
-
   async getReviewMessages(
     channelId?: string,
     limit?: number,
@@ -74,25 +65,6 @@ export class MessagesService {
     logger.debug({ channelId, limit }, "Getting review messages");
     return messagesRepository.getReviewMessages(channelId, limit);
   }
-
-  async reanalyzeErrorBatch(opts: {
-    guildId?: string;
-    channelId?: string;
-    messageIds?: string[];
-  }) {
-    if (
-      !opts.guildId &&
-      !opts.channelId &&
-      (!opts.messageIds || opts.messageIds.length === 0)
-    ) {
-      throw new ValidationError(
-        "At least one of guildId, channelId, or messageIds[] is required",
-      );
-    }
-
-    logger.info(opts, "Batch reanalyzing errored messages");
-    return messagesRepository.reanalyzeErrorBatch(opts);
-  }
 }
 
 export const messagesService = new MessagesService();