feat(gateway): add Tpay (Poland) payment gateway

[hedon77]

Adds a Tpay payment gateway module (Poland) using the Tpay Open API.

What's included

• \modules/Gateways/Tpay/TpayModule.php\ — redirect-based integration (BLIK, quick transfers, cards):
  • OAuth2 client-credentials token (/oauth/auth, \scope=write)
  • create transaction (\POST /transactions) + redirect to Tpay panel
  • refund (\POST /transactions/{id}/refunds)
  • webhook processing with mandatory JWS signature verification (RFC 7515, x5u cert + Tpay root CA) and md5sum check
  • gateway activity written to the panel's system log (\gateway_logs)
• Routes: \gateway/tpay/webhook\ and \gateway/tpay/capture/{invoice}\
• Controller methods \ pay()\ / \ payCapture()\
• Registration in \ModuleServiceProvider\ and \payment_method.tpay\ labels (en/pl)
• Auth coverage for the new capture endpoint in \GatewayCaptureAuthTest\

Config fields

• \client_id\ / \client_secret\ (Open API keys)
• \confirmation_code\ (security code for md5sum)
• \sandbox\ (live/sandbox toggle)

[Panelica]

Excellent, self-contained module that follows the existing gateway pattern and even extends the capture-auth test. One note: the webhook requires the md5sum, which is derived from the security code, so confirmation_code is effectively required despite being marked optional — worth documenting or validating. Great work.

[hedon77]

Good catch — marked confirmation_code as required in the config fields, since the webhook md5sum derives from it.