Add '3STF Tools' entry to resources (#1114)

* Add '3STF Tools' entry to resources

Added a new tool entry for '3STF Tools' with relevant details.

* Change category from 'Tool' to 'Tooling'

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Marcel Cruz <12413903+marcelscruz@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 3 people

resources/0-9.ts

@@ -44,6 +44,14 @@ export const resources: Resource[] = [
         categories: ['Icon'],
         url: 'https://www.3dicons.com/',
     },
+    {
+        name: '3STF Tools',
+        description:
+            'A clean collection of free browser tools for developers, writers, and creators. No accounts. No ads. No data collected.',
+        categories: ['Tool', 'Productivity'],
+        url: 'https://www.3stf.com/',
+        keywords: ['json formatter', 'image converter', 'password generator', 'word counter', 'developer tools', 'free tools', 'privacy', 'client-side'],
+    },
     {
         name: '4 day week',
         description: 'Software jobs with a better work / life balance.',