feat(fusion_clock): native recurring shifts engine [A4-A5]

fusion.clock.schedule.recurrence (repeat every N day/week/month/year;
forever/until/N-times) re-fit from planning.recurrency onto per-day rows;
daily generation cron; _fclk_on_leave skip; planner Repeat…/Stop-repeat
UI + endpoints; recurrence + role indicators on cells.

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

fusion_clock/models/res_company.py

@@ -14,3 +14,14 @@ class ResCompany(models.Model):
         domain="[('company_id', '=', id)]",
         help="Clock location bound to the on-site kiosk (NFC and PIN) for this company.",
     )
+    fclk_planning_generation_months = fields.Integer(
+        string='Schedule Generation Horizon (months)',
+        default=6,
+        help="How many months ahead recurring shifts are pre-generated.",
+    )
+    fclk_self_unassign_days_before = fields.Integer(
+        string='Self-Unassign Cutoff (days before shift)',
+        default=1,
+        help="Employees may release an open shift they claimed up to this many "
+             "days before it starts.",
+    )