fix(transfers): use original membership date for separation fee calculation

When membership transfers via death/waiver, the fee calculator now uses
the original membership creation date instead of the transfer date.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Modules/Death/Controllers/DeathController.php

@@ -862,6 +862,7 @@ class DeathController extends Controller
                     'transferred_from_death_id'  => $caseId,
                     'original_membership_number' => $inheritedNumber,
                     'ownership_transfer_date'    => date('Y-m-d'),
+                    'membership_origin_date'     => $member['membership_origin_date'] ?? $member['form_date'] ?? substr($member['created_at'], 0, 10),
                     'form_number'                => $formData['form_number'] ?? null,
                     'deceased_member_name'       => $member['full_name_ar'],
                     'created_at'                 => date('Y-m-d H:i:s'),

app/Modules/Transfers/Services/SeparationFeeCalculator.php

@@ -57,7 +57,7 @@ final class SeparationFeeCalculator
         }
 
         // Calculate years since acquisition
-        $acquisitionDate = $member['created_at'] ?? $member['form_date'] ?? date('Y-m-d');
+        $acquisitionDate = $member['membership_origin_date'] ?? $member['form_date'] ?? $member['created_at'] ?? date('Y-m-d');
         $yearsSince = self::calculateYearsSince($acquisitionDate);
 
         // Get fee percentage based on years
@@ -257,7 +257,7 @@ final class SeparationFeeCalculator
         }
 
         // Elapsed years: floor from father's membership creation to effective_transfer_date
-        $acquisitionDate = $member['created_at'] ?? $member['form_date'] ?? date('Y-m-d');
+        $acquisitionDate = $member['membership_origin_date'] ?? $member['form_date'] ?? $member['created_at'] ?? date('Y-m-d');
         $yearsSince = self::calculateYearsFloor($acquisitionDate, $effectiveTransferDate);
 
         $feePercentage = self::getFeePercentageByYear($yearsSince);

app/Modules/Waiver/Services/WaiverProcessor.php

@@ -74,6 +74,7 @@ final class WaiverProcessor
                 'activated_at'               => date('Y-m-d H:i:s'),
                 'transferred_from_waiver_id' => $waiverId,
                 'ownership_transfer_date'    => date('Y-m-d'),
+                'membership_origin_date'     => $sourceMember['membership_origin_date'] ?? $sourceMember['form_date'] ?? substr($sourceMember['created_at'], 0, 10),
                 'waived_from_member_name'    => $sourceMember['full_name_ar'] ?? null,
                 'updated_at'                 => date('Y-m-d H:i:s'),
             ], '`id` = ?', [(int) $waiver['target_member_id']]);

database/migrations/Phase_103_005_add_membership_origin_date.php

+<?php
+
+declare(strict_types=1);
+
+use App\Core\Database;
+
+return function (Database $db): void {
+    // Add column
+    $exists = $db->selectOne(
+        "SELECT 1 FROM information_schema.columns WHERE table_schema = DATABASE() AND table_name = 'members' AND column_name = 'membership_origin_date'"
+    );
+
+    if (!$exists) {
+        $db->raw("ALTER TABLE members ADD COLUMN membership_origin_date DATE NULL COMMENT 'Original membership creation date — survives death/waiver transfers' AFTER ownership_transfer_date");
+    }
+
+    // Backfill: death-transferred members
+    $db->raw("
+        UPDATE members m
+        INNER JOIN death_cases dc ON dc.id = m.transferred_from_death_id
+        INNER JOIN members deceased ON deceased.id = dc.member_id
+        SET m.membership_origin_date = COALESCE(deceased.membership_origin_date, deceased.form_date, DATE(deceased.created_at))
+        WHERE m.transferred_from_death_id IS NOT NULL
+          AND m.membership_origin_date IS NULL
+    ");
+
+    // Backfill: waiver-transferred members
+    $db->raw("
+        UPDATE members m
+        INNER JOIN waiver_requests wr ON wr.id = m.transferred_from_waiver_id
+        INNER JOIN members source ON source.id = wr.source_member_id
+        SET m.membership_origin_date = COALESCE(source.membership_origin_date, source.form_date, DATE(source.created_at))
+        WHERE m.transferred_from_waiver_id IS NOT NULL
+          AND m.membership_origin_date IS NULL
+    ");
+};