feat: file upload + expense report creation from Discuss attachments

- Discuss bot now reads ir.attachment from incoming messages; file-only
  messages no longer silently dropped
- ZIP files are described (contents listed) and bot asks clarifying
  question before acting; user's follow-up reply looks back for pending
  attachments so files don't need to be re-uploaded
- receipt_parser: extracts text from ZIP (recursive), JPG/PNG/etc (OCR),
  PDF (pdfplumber), HTML, TXT
- expenses_agent: full rewrite fixing broken method signatures; adds
  create_expense_sheet / create_expense / attach_receipt flow driven by
  LLM receipt parsing (Ollama, HIPAA-locked)
- master_agent: extra_context threads receipts + user_id into directives
- FastAPI /upload multipart endpoint; registered in main.py
- Odoo /ai/upload controller proxies files to agent service
- ab_ai_bot: dispatch_message_with_files() for multipart uploads

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

addons/activeblue_ai/models/ab_ai_bot.py

@@ -111,6 +111,44 @@ class AbAiBot(models.Model):
             _logger.error('dispatch_message failed: %s', exc)
             raise UserError(_('Could not reach AI service: %s') % exc)
 
+    def dispatch_message_with_files(self, user_id, message, attachments, context=None, session_id=None):
+        """Send a message with file attachments to the /upload endpoint as multipart."""
+        self.ensure_one()
+        import base64
+        url = self._get_service_url() + '/upload'
+
+        files = []
+        for att in attachments:
+            try:
+                data = base64.b64decode(att.datas) if att.datas else b''
+                files.append(('files', (att.name or 'attachment',
+                                        data,
+                                        att.mimetype or 'application/octet-stream')))
+            except Exception as exc:
+                _logger.warning('Could not encode attachment %s: %s', att.id, exc)
+
+        # Omit Content-Type so requests sets the multipart boundary automatically
+        headers = {}
+        if self.webhook_secret:
+            headers['X-ActiveBlue-Signature'] = self.webhook_secret
+
+        form_data = {
+            'user_id': str(user_id),
+            'message': message or 'Create an employee expense report from these receipts.',
+            'session_id': session_id or '',
+        }
+
+        try:
+            resp = requests.post(url, data=form_data, files=files or [('files', ('empty', b'', 'text/plain'))],
+                                 headers=headers, timeout=120)
+            resp.raise_for_status()
+            return resp.json()
+        except requests.exceptions.Timeout:
+            raise UserError(_('AI service timed out. Please try again.'))
+        except requests.exceptions.RequestException as exc:
+            _logger.error('dispatch_message_with_files failed: %s', exc)
+            raise UserError(_('Could not reach AI service: %s') % exc)
+
     @api.model
     def cron_ping_all(self):
         any_online = False