Ajout des notification + page employé (#6)

| Numéro du ticket | Titre du ticket |
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## Description de la PR

## Modification du .env

## Check list

- [ ] Pas de régression
- [ ] TU/TI/TF rédigée
- [ ] TU/TI/TF OK
- [ ] CHANGELOG modifié

Reviewed-on: #6
Co-authored-by: tristan <tristan@yuno.malio.fr>
Co-committed-by: tristan <tristan@yuno.malio.fr>

migrations/Version20260304153000.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260304153000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Create employee leave balances table for annual rollover opening balances';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('CREATE TABLE employee_leave_balances (id SERIAL NOT NULL, employee_id INT NOT NULL, rule_code VARCHAR(64) NOT NULL, year INT NOT NULL, opening_days DOUBLE PRECISION NOT NULL, opening_saturdays DOUBLE PRECISION NOT NULL, accrued_days DOUBLE PRECISION NOT NULL, accrued_saturdays DOUBLE PRECISION NOT NULL, taken_days DOUBLE PRECISION NOT NULL, taken_saturdays DOUBLE PRECISION NOT NULL, closing_days DOUBLE PRECISION NOT NULL, closing_saturdays DOUBLE PRECISION NOT NULL, is_locked BOOLEAN DEFAULT FALSE NOT NULL, created_at TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL, updated_at TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL, PRIMARY KEY(id))');
+        $this->addSql('CREATE UNIQUE INDEX uniq_employee_leave_balance ON employee_leave_balances (employee_id, rule_code, year)');
+        $this->addSql('CREATE INDEX idx_leave_balance_employee_year ON employee_leave_balances (employee_id, year)');
+        $this->addSql('ALTER TABLE employee_leave_balances ADD CONSTRAINT FK_3834A8A18C03F15C FOREIGN KEY (employee_id) REFERENCES employees (id) ON DELETE CASCADE NOT DEFERRABLE INITIALLY IMMEDIATE');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('DROP TABLE employee_leave_balances');
+    }
+}