[Bug]: APIs for gateways in admin and main do not mask auth values

[kevalmahajan]

🐞 Bug Summary

The APIs used to retrieve gateway information in both the admin and main interfaces fail to mask authentication values. As a result, all authentication tokens, credentials, and sensitive information for each gateway are exposed in the responses, which can lead to sensitive data being exposed unintentionally.

APIs include GET methods for:

1. /admin/gateways
2. /admin/gateways/{gateway_id}
3. /gateways
4. /gateways/{gateway_id}

---

🧩 Affected Component

Select the area of the project impacted:

• mcpgateway - API
• mcpgateway - UI (admin panel)
• mcpgateway.wrapper - stdio wrapper
• Federation or Transports
• CLI, Makefiles, or shell scripts
• Container setup (Docker/Podman/Compose)
• Other (explain below)

---

🔁 Steps to Reproduce

1. Launch the mcpgateway service.
2. Open your browser and go to http://localhost:4444/admin/gateways and for other URLs mentioned above, or send a GET request to the same URL.
3. The authentication credentials for all gateways will be exposed.

---

🤔 Expected Behavior

The Auth values should be masked as per needed.

For eg. if the authType is bearer, authValue and authToken should be masked.

    "authType": "bearer",
    "authValue": "*****",
    "authUsername": null,
    "authPassword": null,
    "authToken": "*****",
    "authHeaderKey": null,
    "authHeaderValue": null,

Similarly for all the other authTypes too

---

📓 Logs / Error Output

Paste any relevant stack traces or logs here.
⚠️ Do not paste secrets, credentials, or tokens.

---

🧠 Environment Info

You can retrieve most of this from the /version endpoint.

Key	Value
Version or commit	e.g. v0.9.0 or main@a1b2c3d
Runtime	e.g. Python 3.11, Gunicorn
Platform / OS	e.g. Ubuntu 22.04, macOS
Container	e.g. Docker, Podman, none

---

🧩 Additional Context (optional)

Add any configuration details, flags, or related issues.