stock_move_line_change_lot: add hooks before/after moves reservation

Port of hooks that were added in `shopfloor` 14.0 after that this module
was extracted from `shopfloor` during migration to 16.0:

- OCA/wms/pull/712/commits/c296499726f0f95082bfe40bfb0c137dfd2fb690
- OCA/wms/pull/945/commits/28d4a0116e9c891cd1f37e794e3a7643798260ac

stock_move_line_change_lot/models/stock_move_line.py

@@ -2,6 +2,8 @@
 # Copyright 2024 Jacques-Etienne Baudoux (BCIM) <je@bcim.be>
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
+from collections import defaultdict
+
 from odoo import _, models
 from odoo.exceptions import UserError
 from odoo.tools.float_utils import float_compare
@@ -69,6 +71,7 @@ def write(self, vals):
         res = True
         already_processed = self.browse()
         to_reassign_moves = self.env["stock.move"]
+        moves_by_previous_lot = defaultdict(self.env["stock.move"].browse)
         lot = self.env["stock.lot"].browse(vals["lot_id"])
         for move_line in self:
             if move_line.move_id._should_bypass_reservation(move_line.location_id):
@@ -87,6 +90,7 @@ def write(self, vals):
             package = move_line.package_id.browse(
                 vals.get("package_id", move_line.package_id)
             )
+            moves_by_previous_lot[move_line.lot_id] |= move_line.move_id
 
             available_quantity = 0
             # Collect new lot inside or outside a package (strict=False)
@@ -161,6 +165,25 @@ def write(self, vals):
         res &= super(StockMoveLine, self - already_processed).write(vals)
 
         if to_reassign_moves:
-            to_reassign_moves._action_assign()
+            self._handle_change_lot_reassign(
+                lot, to_reassign_moves, moves_by_previous_lot
+            )
 
         return res
+
+    def _handle_change_lot_reassign(
+        self, lot, to_reassign_moves, moves_by_previous_lot
+    ):
+        for previous_lot, moves in moves_by_previous_lot.items():
+            moves &= to_reassign_moves
+            self._hook_change_lot_before_assign(previous_lot, lot, moves)
+        to_reassign_moves._action_assign()
+        for previous_lot, moves in moves_by_previous_lot.items():
+            moves &= to_reassign_moves
+            self._hook_change_lot_after_assign(previous_lot, lot, moves)
+
+    def _hook_change_lot_before_assign(self, previous_lot, lot, moves):
+        pass
+
+    def _hook_change_lot_after_assign(self, previous_lot, lot, moves):
+        pass