Improve messaging and dashboard reliability

src/main-loop.ts

@@ -85,6 +85,7 @@ export async function runMainLoop(app: AppContainer): Promise<void> {
     accountAuth,
     postsRepo,
     messagesRepo,
+    recipientDeduplicator,
     redditApi,
     monitorService,
     processorService,
@@ -290,17 +291,35 @@ export async function runMainLoop(app: AppContainer): Promise<void> {
 
           await rateLimiter.throttle(
             async () => {
+              if (!recipientDeduplicator.tryReserve(post.author)) {
+                const reason = 'User already contacted across accounts';
+                logger.info(`Skipping u/${post.author} - ${reason.toLowerCase()}`);
+                postsRepo.setError(post.id, reason);
+                webServer?.logActivity(
+                  'skipped',
+                  `Skipped u/${post.author} (already contacted across accounts)`,
+                  post.author,
+                );
+                return false;
+              }
+
               logger.info(`Sending message to u/${post.author}...`);
               webServer?.pushLog('info', `Sending message to u/${post.author}...`);
 
-              const chat = await chatService.startConversation(
-                post.author,
-                processed.generatedMessage,
-                post.author_fullname,
-              );
+              let chat;
+              try {
+                chat = await chatService.startConversation(
+                  post.author,
+                  processed.generatedMessage,
+                  post.author_fullname,
+                );
+              } catch (error) {
+                recipientDeduplicator.release(post.author);
+                throw error;
+              }
               const success = chat !== null;
 
-              if (success) {
+              if (chat) {
                 postsRepo.markMessageSent(post.id);
 
                 // Refresh top chats in background so dashboard is up-to-date.
@@ -340,6 +359,7 @@ export async function runMainLoop(app: AppContainer): Promise<void> {
                   });
                 }
               } else {
+                recipientDeduplicator.release(post.author);
                 postsRepo.setError(post.id, 'Failed to send message');
                 webServer?.logActivity(
                   'error',