feat(fusion_clock): native shift roles (fusion.clock.role) [A1-A3]

Replaces Odoo Planning's planning.role: name+colour model with the same
1-11 palette, employee default/allowed role fields, Employee Roles editor,
role_id on shift template + schedule with default resolution, ACLs, menus.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fusion_clock/models/clock_shift.py

@@ -42,6 +42,12 @@ class FusionClockShift(models.Model):
     )
     active = fields.Boolean(default=True)
     color = fields.Char(string='Color', default='#3B82F6')
+    role_id = fields.Many2one(
+        'fusion.clock.role',
+        string='Default Role',
+        help="Role assigned to shifts created from this template "
+             "(drives the colour/label on the employee's portal schedule).",
+    )
 
     # Weekday pattern — which days this recurring shift applies as the baseline
     # when there is no posted planner entry for the day. Default Mon-Fri.