Add link to view available models for the current epoch in quickstart.md

[huxuxuya]

Improve Model Configuration Discoverability in Quickstart Guide

Problem

It is not immediately obvious where users should look to find information about which models they can configure in their node-config.json settings. Currently, the documentation shows:

1. Hardcoded model examples in the configuration sections (lines 215-277) with specific model names like Qwen/Qwen3-235B-A22B-Instruct-2507-FP8 and Qwen/Qwen3-32B-FP8
2. A note about currently supported models (lines 212-213) that may become outdated
3. Information about checking available models via the governance API (lines 282-285) that appears after the configuration examples

Issue

Users following the quickstart guide are presented with configuration examples that include hardcoded model names, but there's no clear guidance upfront on:

• How to discover which models are actually available for the current epoch
• Where to find the authoritative source of model information
• How to verify that the model they want to configure is supported

The governance API endpoint (http://node2.gonka.ai:8000/v1/governance/models) is mentioned, but it's placed after the configuration sections, making it easy for users to miss this critical information when they're trying to configure their nodes.

Proposed Solution

Restructure the documentation to:

1. Prominently highlight the governance API endpoint before showing configuration examples
2. Explain that users should check the governance API to see which models are available for the current epoch
3. Emphasize that model availability can change and users should always verify against the governance endpoint rather than relying on hardcoded examples
4. Provide clear guidance on how to use the information from the governance API to configure node-config.json

This will make it much clearer to users where to find the authoritative information about available models before they attempt to configure their nodes.