feat: add star & spread-the-word nudges to sponsorship section

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: trakhimenok

index.html

@@ -636,6 +636,18 @@ <h2 style="font-family:var(--font-display);font-size:clamp(28px,4vw,44px);font-w
                class="btn-primary" style="text-decoration:none;display:inline-flex;align-items:center;gap:10px;font-size:13px;padding:14px 28px;letter-spacing:0.08em;">
                 <span style="font-size:15px;line-height:1;">♥</span> Sponsor on GitHub
             </a>
+            <div style="margin-top:24px;display:flex;flex-direction:column;gap:10px;">
+                <p style="font-family:var(--font-mono);font-size:11px;color:var(--text-muted);margin:0;">
+                    Not in a position to sponsor?
+                    <a href="https://github.com/ingr-io/ingr-file-format" target="_blank" rel="noopener"
+                       class="link-accent" style="font-family:var(--font-mono);font-size:11px;">⭐ A star on GitHub</a>
+                    costs nothing and helps others discover the project.
+                </p>
+                <p style="font-family:var(--font-mono);font-size:11px;color:var(--text-muted);margin:0;">
+                    Using INGR at work or in a project?
+                    Tell a colleague, write a post, or just mention it — word of mouth is everything for open-source.
+                </p>
+            </div>
         </div>
         <div style="display:flex;justify-content:center;align-items:center;">
             <div class="sponsor-terminal">