feat: pre-creation confirmation step with inline duplicate warnings

Before writing any expense records the bot now posts a numbered table
of parsed vendor/amount/date for every receipt, with duplicate entries
flagged inline. User replies 'confirm' (skips dups) or 'confirm, keep
all'. This catches OCR amount misreads before they land in Odoo.

Also removes the separate awaiting_dup_approval step; duplicate review
is now part of the single confirmation table.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

addons/activeblue_ai/models/ab_ai_mail.py

@@ -273,6 +273,8 @@ class DiscussChannel(models.Model):
             'suspected duplicate',
             'skip duplicates',
             'keep all',
+            'please review',
+            'reply "confirm"',
         )
         prev_was_bot_question = False
         for msg in messages: