Gmail folder auto-advance + /forward command

- Reply-cycle auto-advance: staff reply files the thread to "Awaiting Reply",
  a customer response files it to "Needs Response" (new GMAIL_LABEL_AWAITING_REPLY
  / GMAIL_LABEL_NEEDS_RESPONSE labels + autoAdvanceFolder, which only moves
  threads still in the auto-cycle and leaves hand-filed folders alone)
- /forward: forward a ticket's email to another address (handlers/commands/forward.js
  + forward composition in services/gmail.js)
- Tests for the auto-advance cycle; label fixtures updated for the new labels

gmail-poll.js

@@ -21,7 +21,7 @@ const {
   sanitizeEmbedText
 } = require('./utils');
 const { getGmailClient } = require('./services/gmail');
-const { moveThreadToFolder } = require('./services/gmailLabels');
+const { moveThreadToFolder, autoAdvanceFolder } = require('./services/gmailLabels');
 const { getNextTicketNumber, checkTicketLimits, getOrCreateTicketCategory, toDiscordSafeName, getSenderLocal } = require('./services/tickets');
 const { logError } = require('./services/debugLog');
 const { enqueueSend } = require('./services/channelQueue');
@@ -305,10 +305,22 @@ async function poll(client) {
             content: `**New Follow-up from ${parsed.senderEmail}:**\n${truncatedFollowup}`,
             allowedMentions: { parse: [] }
           });
-          // Follow-up on an existing thread: archive the new message only. Leave
-          // whatever managed folder staff filed this thread under untouched.
-          console.log('Archiving/reading Gmail message', msgRef.id);
-          await markGmailMessageRead(gmail, msgRef);
+          // Customer responded → advance the thread to Needs Response. A
+          // successful move strips INBOX+UNREAD (archives + marks read like
+          // markGmailMessageRead did). If the thread is manually filed (For Jake,
+          // Spam, …) autoAdvanceFolder leaves it put and returns false — or the
+          // move may fail — so in either case fall back to marking just the new
+          // message read, preserving the manual filing and avoiding reprocessing.
+          let advanced = false;
+          try {
+            advanced = await autoAdvanceFolder(parsed.threadId, 'NEEDS_RESPONSE', gmail);
+          } catch (err) {
+            logError('autoAdvanceFolder(NEEDS_RESPONSE)', err, null, client).catch(() => {});
+          }
+          if (!advanced) {
+            console.log('Archiving/reading Gmail message', msgRef.id);
+            await markGmailMessageRead(gmail, msgRef);
+          }
         } else {
           // Create a new ticket channel.
           const limitCheck = await checkTicketLimits(parsed.senderEmail);