fix(companies): correct sponsor filtering logic for table display

- Update sponsor filter to explicitly check for 'gold' or 'silver' values
- Update non-sponsor filter to exclude 'gold' and 'silver' values
- Prevents empty string issues from incorrectly categorizing companies

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: mrleeio

companies.html

@@ -21,7 +21,7 @@ <h2 class="text-center fw-semibold">Companies Hiring Ruby Developers in Vancouve
 </div>
 
 <!-- Sponsor Companies Table -->
-{% assign sponsors = site.data.companies | where_exp: "company", "company.sponsor_tier != ''" %}
+{% assign sponsors = site.data.companies | where_exp: "company", "company.sponsor_tier == 'gold' or company.sponsor_tier == 'silver'" %}
 {% if sponsors.size > 0 %}
 <div class="mb-5 mt-5">
   <h3 class="mb-3">
@@ -69,7 +69,7 @@ <h3 class="mb-3">
 {% endif %}
 
 <!-- All Other Companies Table -->
-{% assign non_sponsors = site.data.companies | where_exp: "company", "company.sponsor_tier == ''" %}
+{% assign non_sponsors = site.data.companies | where_exp: "company", "company.sponsor_tier != 'gold' and company.sponsor_tier != 'silver'" %}
 <div class="mb-4 mt-5">
   <h3 class="mb-3">
     Other Ruby Employers