Fix category page 404 errors and add Water Management category

[Copilot]

Category icons were returning 404s due to missing Water Management page and a data source bug in the category layout that prevented all category pages from displaying tools.

Core Fix

_layouts/category.html: Changed data source from site.tools (Jekyll collection with 1 file) to site.data.tools (YAML file with 12 tools):

  <div class="tool-grid">
-     {% for tool in site.tools %}
+     {% for tool in site.data.tools %}
          {% if tool.categories contains page.category %}
              {% include tool-card.html tool=tool %}
          {% endif %}
      {% endfor %}
  </div>

This fixes all category pages (energy, heat, flood, etc.), not just the ones mentioned in the issue.

Water Management Category

• Created /categories/water.md with standard category page structure
• Added water category to 3 relevant tools: Stormwater Calculator, NOAA Sea Level Rise Viewer, Green Infrastructure Coalition
• Added navigation cards to index.md and categories/index.md with water wave SVG icon
• Added Water Management filter option to tools.md

Impact

All 9 category pages now functional with proper tool filtering. Water Management displays 3 tools.

Original prompt

When clicking on icons like 'Energy Efficiency' or 'Water Management', a 404 error occurs. These icons should redirect to a page where all tools in the respective category are displayed in a table.

Tasks

1. Fix the 404 errors for the following icons by ensuring they redirect to the correct pages:
   • Energy Efficiency
   • Water Management
2. Create pages for each category with a table displaying all tools in that category.
3. Set up the tool database and populate it with the necessary data for all tool categories.
4. Implement functionality to filter the tools on each page by their respective category.
5. Test to ensure all the icon links work correctly and the category pages are functional with filtered tool views.
6. Update the README or relevant documentation to reflect changes made.

This pull request was created from Copilot chat.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.