Add Green Sage AI plant-care web app

[skyestrela]

📝 New Tool Information

• Tool Name: Green Sage
• Description: Browser-based AI plant identification and visible-symptom guidance with free tools and no app-store install.
• Tool URL: https://www.greensage.co.uk/
• Altern.ai page link: N/A

📌 Description

Adds one AI plant-care web app to the end of the Other category.

✅ Checklist

• I reviewed the repository instructions and pull request template
• Only one tool is modified in this PR
• All available fields are provided
• The tool link is valid and accessible (HTTP 200 verified)
• The tool is not already listed
• The tool is placed at the end of the Other category
• No unrelated changes included

🛠 Type of Change

• 📚 Documentation / README update
• ➕ Adding a new AI tool

💡 Additional Notes

The listing links only to the public product website. No private source repository or credentials are included.