fix(fusion_helpdesk): define missing _norm_email helper (NameError on every inbox endpoint)

The IDOR-hardening commit (fb345be3) referenced _norm_email in submit()
and _identity() but never defined or imported it, so every inbox endpoint
(my_tickets, ticket_detail, ticket_reply, unread_count) and the New-ticket
submit path raised NameError at runtime — surfaced as a JSON-RPC error in
the dialog. The smoke test missed it because it replicated build_scope_domain
directly instead of calling the controller.

Add _norm_email(*candidates) to utils.py (returns the first candidate that
email_normalize accepts, else '' — rejecting self-set wildcards like '%' so
the inbox scope key can't be widened), import it in main.py, drop the now-unused
email_normalize import there, and add unit tests + a guard that the controller
namespace resolves the name.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_helpdesk/controllers/main.py

@@ -22,7 +22,6 @@ from urllib.parse import urljoin, urlparse
 from odoo import _, http
 from odoo.exceptions import UserError
 from odoo.http import request
-from odoo.tools import email_normalize
 
 from odoo.addons.fusion_helpdesk.utils import (
     build_ticket_vals,
@@ -30,6 +29,7 @@ from odoo.addons.fusion_helpdesk.utils import (
     is_public_message,
     compute_unread_count,
     escape_like,
+    _norm_email,
 )
 
 _logger = logging.getLogger(__name__)