feat: add Pixelfed to social links (#4767)

Add Pixelfed as a supported social platform, including the platform
entry in socialHandle.go and the SVG icon.

Closes #4726

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

models/socialHandle.go

@@ -136,6 +136,10 @@ func GetAllSocialHandles() map[string]SocialHandle {
 			Platform: "Follow",
 			Icon:     "/img/platformlogos/follow.svg",
 		},
+		"pixelfed": {
+			Platform: "Pixelfed",
+			Icon:     "/img/platformlogos/pixelfed.svg",
+		},
 		"peertube": {
 			Platform: "Peertube",
 			Icon:     "/img/platformlogos/peertube.svg",

web/public/img/platformlogos/pixelfed.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="#fff"><path d="M12 24C5.3726 24 0 18.6274 0 12S5.3726 0 12 0s12 5.3726 12 12-5.3726 12-12 12m-.9526-9.3802h2.2014c2.0738 0 3.7549-1.6366 3.7549-3.6554S15.3226 7.309 13.2488 7.309h-3.1772c-1.1964 0-2.1663.9442-2.1663 2.1089v8.208z"/></svg>