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/utils.py

@@ -8,6 +8,7 @@ here is unit-testable in isolation, which is what lets us validate the
 identity keystone, the server-side scoping boundary, the public-message
 filter and the unread maths without a live central Odoo to talk to.
 """
+from odoo.tools import email_normalize
 
 # Sentinel used so a missing label/email can never widen a domain to
 # "match everything". An empty string in `=`/`=ilike` would match rows
@@ -29,6 +30,24 @@ def escape_like(value):
     return (value or '').replace('\\', '\\\\').replace('%', '\\%').replace('_', '\\_')
 
 
+def _norm_email(*candidates):
+    """Return the first candidate that normalises to a valid email, else ''.
+
+    Used to derive the inbox scope key from a chain of fallbacks (the
+    confirmed reply email -> ``user.email`` -> ``user.login``).
+    ``email_normalize`` lowercases the address and returns a falsy value for
+    anything that is not exactly one valid email — including a self-set
+    wildcard like ``%`` — so the value fed into ``build_scope_domain`` can
+    never widen the scope. Pairs with :func:`escape_like` as defense in depth
+    against the ``partner_email =ilike`` IDOR.
+    """
+    for candidate in candidates:
+        normalized = email_normalize(candidate or '')
+        if normalized:
+            return normalized
+    return ''
+
+
 def build_ticket_vals(kind, subject, body_html, team_id, client_label,
                       reporter_name, reporter_email, company_name):
     """Construct the `helpdesk.ticket` create vals for a forwarded report.