feat(seo): swap the generated OG image for the designer-refined one (Gitea #4)

Replaces the code-generated opengraph-image.tsx (placeholder circles,
default font) with a static opengraph-image.png exported from the
designer's refined SVG — a properly-shaped paw mark and a different
typeface. The source SVG traces letterforms as vector paths and embeds
a raster background, which isn't practical to reproduce in a
next/og ImageResponse component, so it's shipped as a static asset
via Next.js's file-convention instead (same og:image/twitter:image
wiring, no proxy.ts change needed — same route path as before).

src/app/opengraph-image.alt.txt

@@ -0,0 +1 @@
+PawFeed — the social platform where pets are the stars.

src/app/opengraph-image.tsx

@@ -1,105 +0,0 @@
-import { ImageResponse } from "next/og";
-
-export const alt = "PawFeed — the social platform where pets are the stars.";
-export const size = { width: 1200, height: 630 };
-export const contentType = "image/png";
-
-// Simple 1-big-pad + 4-toes paw print, built from plain positioned circles —
-// Satori's CSS support doesn't need raw SVG for a shape this simple.
-function PawMark({ scale = 1, opacity = 1 }: { scale?: number; opacity?: number }) {
-  const s = (n: number) => n * scale;
-  return (
-    <div style={{ position: "relative", width: s(340), height: s(340), opacity, display: "flex" }}>
-      <div
-        style={{
-          position: "absolute",
-          left: s(70),
-          top: s(140),
-          width: s(200),
-          height: s(170),
-          borderRadius: "50% 50% 45% 45%",
-          background: "#FFFFFF",
-        }}
-      />
-      <div style={{ position: "absolute", left: s(30), top: s(30), width: s(90), height: s(110), borderRadius: "50%", background: "#FFFFFF" }} />
-      <div style={{ position: "absolute", left: s(140), top: s(0), width: s(90), height: s(115), borderRadius: "50%", background: "#FFFFFF" }} />
-      <div style={{ position: "absolute", left: s(250), top: s(30), width: s(90), height: s(110), borderRadius: "50%", background: "#FFFFFF" }} />
-      <div style={{ position: "absolute", left: s(-20), top: s(120), width: s(80), height: s(100), borderRadius: "50%", background: "#FFFFFF" }} />
-    </div>
-  );
-}
-
-export default function Image() {
-  return new ImageResponse(
-    (
-      <div
-        style={{
-          width: "100%",
-          height: "100%",
-          display: "flex",
-          background: "linear-gradient(135deg, #FB923C 0%, #F97316 45%, #C2410C 100%)",
-          position: "relative",
-        }}
-      >
-        {/* Decorative oversized paw mark bleeding off the right edge — depth/layering */}
-        <div style={{ position: "absolute", right: -60, top: -40, display: "flex" }}>
-          <PawMark scale={2.05} opacity={0.16} />
-        </div>
-
-        {/* Content column */}
-        <div
-          style={{
-            display: "flex",
-            flexDirection: "column",
-            justifyContent: "center",
-            paddingLeft: 96,
-            paddingRight: 96,
-            width: "100%",
-            height: "100%",
-          }}
-        >
-          <div style={{ display: "flex", alignItems: "center", marginBottom: 28 }}>
-            <PawMark scale={0.62} />
-          </div>
-          <div
-            style={{
-              display: "flex",
-              fontSize: 132,
-              fontWeight: 800,
-              color: "#FFFFFF",
-              letterSpacing: -3,
-              lineHeight: 1,
-            }}
-          >
-            PawFeed
-          </div>
-          <div
-            style={{
-              display: "flex",
-              fontSize: 40,
-              fontWeight: 500,
-              color: "#FFF7ED",
-              marginTop: 22,
-              maxWidth: 820,
-            }}
-          >
-            Where pets are the stars.
-          </div>
-          <div
-            style={{
-              display: "flex",
-              fontSize: 26,
-              fontWeight: 600,
-              color: "#FFEDD5",
-              marginTop: 44,
-              letterSpacing: 1,
-            }}
-          >
-            pawfeed.org
-          </div>
-        </div>
-      </div>
-    ),
-    { ...size }
-  );
-}