feat(fusion_clock): multi-day leave requests (date range)

Request Leave now takes a From/To date range instead of a single day (the To
field is optional -> single-day). Added date_to to fusion.clock.leave.request
(start kept as leave_date), with overlap detection on submit and a date_to >=
leave_date constraint. The absence check and reports now treat a leave as
covering its whole span. The form shows two date inputs; the controller accepts
date_from/date_to (the old single leave_date payload is still honoured). A
migration backfills date_to = leave_date for existing rows.

Live and verified on entech 19.0.3.13.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

fusion_clock/models/clock_leave_request.py

@@ -3,7 +3,8 @@
 # License OPL-1 (Odoo Proprietary License v1.0)
 
 import logging
-from odoo import models, fields, api
+from odoo import models, fields, api, _
+from odoo.exceptions import ValidationError
 
 _logger = logging.getLogger(__name__)
 
@@ -23,10 +24,16 @@ class FusionClockLeaveRequest(models.Model):
         ondelete='cascade',
     )
     leave_date = fields.Date(
-        string='Leave Date',
+        string='From Date',
         required=True,
         index=True,
     )
+    date_to = fields.Date(
+        string='To Date',
+        index=True,
+        help="Last day of the leave (inclusive); equals the start date for a "
+             "single-day request.",
+    )
     reason = fields.Text(
         string='Reason',
         required=True,
@@ -59,15 +66,32 @@ class FusionClockLeaveRequest(models.Model):
         store=True,
     )
 
-    @api.depends('employee_id', 'leave_date')
+    @api.depends('employee_id', 'leave_date', 'date_to')
     def _compute_display_name(self):
         for rec in self:
             emp = rec.employee_id.name or ''
-            date_str = str(rec.leave_date) if rec.leave_date else ''
-            rec.display_name = f"{emp} - Leave ({date_str})"
+            rec.display_name = f"{emp} - Leave ({rec._fclk_date_label()})"
+
+    def _fclk_date_label(self):
+        """Human label for the leave period: a single date, or 'from to to'."""
+        self.ensure_one()
+        if not self.leave_date:
+            return ''
+        if self.date_to and self.date_to != self.leave_date:
+            return f"{self.leave_date} to {self.date_to}"
+        return str(self.leave_date)
+
+    @api.constrains('leave_date', 'date_to')
+    def _check_leave_dates(self):
+        for rec in self:
+            if rec.date_to and rec.leave_date and rec.date_to < rec.leave_date:
+                raise ValidationError(_("The end date cannot be before the start date."))
 
     @api.model_create_multi
     def create(self, vals_list):
+        for vals in vals_list:
+            if not vals.get('date_to') and vals.get('leave_date'):
+                vals['date_to'] = vals['leave_date']
         records = super().create(vals_list)
         for rec in records:
             rec._notify_office_user()
@@ -86,7 +110,7 @@ class FusionClockLeaveRequest(models.Model):
         try:
             self.env['mail.activity'].sudo().create({
                 'activity_type_id': self.env.ref('mail.mail_activity_data_todo').id,
-                'summary': f"Leave Request: {self.employee_id.name} on {self.leave_date}",
+                'summary': f"Leave Request: {self.employee_id.name} ({self._fclk_date_label()})",
                 'note': f"Reason: {self.reason}",
                 'user_id': office_user.id,
                 'res_model_id': self.env['ir.model']._get_id('fusion.clock.leave.request'),
@@ -102,7 +126,7 @@ class FusionClockLeaveRequest(models.Model):
             self.env['fusion.clock.activity.log'].sudo().create({
                 'employee_id': self.employee_id.id,
                 'log_type': 'leave_request',
-                'description': f"Leave requested for {self.leave_date}: {self.reason}",
+                'description': f"Leave requested for {self._fclk_date_label()}: {self.reason}",
                 'source': 'portal' if self.created_from == 'portal' else 'system',
             })
         except Exception as e: