feat(securite): encrypt SMTP passwords and NocoDB tokens at rest, log supplier mails

Encryption (server/crypto.ts):
- AES-256-GCM with a key derived from ENCRYPTION_KEY, falling back to
  SESSION_SECRET so existing deployments need no new configuration
- stored format enc:v1:<iv>:<tag>:<data>; encryption is idempotent and
  decryption passes legacy plaintext through unchanged, so nothing breaks
  mid-migration
- tampered data or a changed key raises an explicit error instead of
  returning garbage
- encrypt/decrypt is confined to the storage layer: group writes encrypt
  smtpPassword (decrypted only in emailService at connection time, never sent
  to the client), NocoDB config writes encrypt apiToken and reads decrypt it
  so the invoice verification and the admin page behave as before
- startup migration sweep encrypts secrets already stored in plaintext,
  idempotently; the active-config log line no longer prints the token

Mail history (supplier_mail_logs):
- every send attempt is recorded: delivery, store, supplier, recipient,
  subject, status sent/failed with error, message id, user id and name;
  a logging failure never fails the send itself
- GET /api/supplier-mail-logs restricted to the user's stores (admin may
  filter by store)
- on the reconciliation page the mail icon turns green once a request has
  been sent, with the date and sender in the tooltip; clicking again resends
- table created in init.sql, versioned migrations and the production
  startup migration, with delivery/group indexes

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FHdE9nEh8zHhQNGpCgrtYe

server/migrations.ts

@@ -84,6 +84,28 @@ WHERE NOT EXISTS (SELECT 1 FROM webhook_bap_config);`
           ALTER TABLE groups ADD COLUMN IF NOT EXISTS smtp_sender_email VARCHAR(255);
           ALTER TABLE groups ADD COLUMN IF NOT EXISTS smtp_sender_name VARCHAR(255);
         `
+      },
+      {
+        filename: '20260814000001_create_supplier_mail_logs.sql',
+        content: `
+          CREATE TABLE IF NOT EXISTS supplier_mail_logs (
+            id SERIAL PRIMARY KEY,
+            delivery_id INTEGER NOT NULL,
+            group_id INTEGER NOT NULL,
+            supplier_id INTEGER,
+            supplier_name VARCHAR(255),
+            sent_to VARCHAR(255) NOT NULL,
+            subject TEXT,
+            status VARCHAR(20) NOT NULL,
+            error_message TEXT,
+            message_id VARCHAR(255),
+            sent_by VARCHAR NOT NULL,
+            sent_by_name VARCHAR(255),
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+          );
+          CREATE INDEX IF NOT EXISTS idx_supplier_mail_logs_delivery ON supplier_mail_logs(delivery_id);
+          CREATE INDEX IF NOT EXISTS idx_supplier_mail_logs_group ON supplier_mail_logs(group_id);
+        `
       }
     ];