feat(manage): add SetGrantTypeTokenCfg for custom grant type support

[SxxSolar]

Summary

• Add SetGrantTypeTokenCfg(gt oauth2.GrantType, cfg *Config) method to Manager struct to enable custom grant type configuration

Problem

The Manager struct has a private gtcfg field (map[oauth2.GrantType]*Config), but only provides configuration methods for the 4 standard OAuth2 grant types:

• SetAuthorizeCodeTokenCfg
• SetImplicitTokenCfg
• SetPasswordTokenCfg
• SetClientTokenCfg

This design prevents users from configuring custom grant types, which is a common requirement in OAuth2 implementations (e.g., device_code, urn:ietf:params:oauth:grant-type:jwt-bearer, etc.).

Solution

Add a generic SetGrantTypeTokenCfg(gt oauth2.GrantType, cfg *Config) method that allows users to configure token settings for any grant type, including custom ones.

Usage Example

// Define a custom grant type
const DeviceCodeGrant oauth2.GrantType = "urn:ietf:params:oauth:grant-type:device_code"
 
// Configure the custom grant type
manager.SetGrantTypeTokenCfg(DeviceCodeGrant, &manage.Config{
    AccessTokenExp:    time.Hour * 2,
    RefreshTokenExp:   time.Hour * 24 * 7,
    IsGenerateRefresh: true,
})