feat(oauthserver): add authorization list and revoke endpoints

[cemalkilic]

Summary

This PR adds user-facing endpoints that allow users to view and revoke their OAuth 2.1 client authorizations. This will allow users control over which applications have access to their accounts.

Changes

New Endpoints

GET /user/oauth/authorizations

Lists all OAuth clients the authenticated user has authorized.

Response:

{
  "authorized_clients": [
    {
      "client_id": "uuid",
      "client_name": "Example App",
      "client_uri": "https://example.com",
      "logo_uri": "https://example.com/logo.png",
      "scopes": ["read", "write"],
      "granted_at": "2025-10-29T12:00:00Z"
    }
  ]
}

DELETE /user/oauth/authorizations?client_id={client_id}

Revokes authorization for a specific OAuth client.

Actions performed:

• Marks the user's consent as revoked
• Deletes all active sessions associated with the OAuth client
• Creates an audit log entry

Response: 204 No Content on success

[coveralls]

Pull Request Test Coverage Report for Build 19095215430

Details

• 73 of 91 (80.22%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 68.355%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/api/oauthserver/handlers.go	65	83	78.31%

Totals
Change from base Build 19065361991:	0.3%
Covered Lines:	13997
Relevant Lines:	20477

---

💛 - Coveralls