feat(colophon): add a Ko-fi link, and group the author's links together

The link sits last in the existing row beside @StereotypicalCat and Source
code, in that row's own muted grey, with the same hover and the same small
mark. No accent colour, no button, no sentence asking for anything, and the
footer still contains no appeal anywhere — a test asserts that. This page earns
its keep by being trusted about dates, and a tip jar competing with the
disclaimer two paragraphs above spends that trust to make an ask. As one more
link it costs nothing and is there for a reader already looking.

The row also moves above "Additional ideas and design from". That row is who
built this and where to find them; the credit below it is other people. Reading
order now follows that split, instead of routing a reader past five strangers'
handles to reach the author's own links.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

src/client/components/Colophon.tsx

@@ -37,6 +37,7 @@ export const AUTHOR = {
   name: "Lucas Winther",
   site: "https://lucaswinther.info",
   github: "https://github.com/StereotypicalCat",
+  kofi: "https://ko-fi.com/stereotypicalcat",
 } as const;
 
 const LINK =
@@ -98,6 +99,15 @@ function GitHubMark() {
   );
 }
 
+function KofiMark() {
+  return (
+    <svg viewBox="0 0 16 16" className="size-3.5" fill="currentColor" aria-hidden>
+      <path d="M2 3h9.2a3.3 3.3 0 0 1 0 6.6h-.6A4 4 0 0 1 6.7 13H5.3a4 4 0 0 1-4-4V3.7c0-.4.3-.7.7-.7Zm8.6 5.3h.6a2 2 0 0 0 0-4h-.6v4Z" />
+      <path d="M4.4 5.6c.5-.5 1.2-.4 1.6 0 .4-.4 1.1-.5 1.6 0 .5.5.4 1.2 0 1.7L6 8.9 4.4 7.3c-.4-.5-.5-1.2 0-1.7Z" />
+    </svg>
+  );
+}
+
 /** Display name and homepage for a source host. */
 const SITES: Record<string, { name: string; url: string }> = {
   "game8.co": { name: "Game8", url: "https://game8.co" },
@@ -288,26 +298,6 @@ export function Colophon({
         {"."}
       </p>
 
-      {IDEA_CREDITS.length > 0 && (
-        <p className="mt-2">
-          Additional ideas and design from{" "}
-          {IDEA_CREDITS.map((c, i) => (
-            <span key={c.handle}>
-              {i > 0 && (i === IDEA_CREDITS.length - 1 ? " and " : ", ")}
-              <a
-                href={c.url}
-                target="_blank"
-                rel="noreferrer noopener"
-                className={LINK}
-              >
-                {c.handle}
-              </a>
-            </span>
-          ))}
-          {"."}
-        </p>
-      )}
-
       <p className="mt-2 flex flex-wrap items-center gap-x-4 gap-y-1.5">
         <a
           href={AUTHOR.github}
@@ -327,8 +317,45 @@ export function Colophon({
           <GitHubMark />
           Source code
         </a>
+        {/*
+          Last in the row of small links, in the row's own muted grey, with no
+          accent colour, no button and no sentence asking for anything. This
+          page's job is to be trusted about dates, and a tip jar that competes
+          with the disclaimer above it spends that trust to make an ask — so it
+          reads as one more link for a reader already looking at the footer, and
+          is invisible to everyone else.
+        */}
+        <a
+          href={AUTHOR.kofi}
+          target="_blank"
+          rel="noreferrer noopener me"
+          className="inline-flex items-center gap-1.5 text-muted transition-colors duration-150 hover:text-ink"
+        >
+          <KofiMark />
+          Ko-fi
+        </a>
       </p>
 
+      {IDEA_CREDITS.length > 0 && (
+        <p className="mt-2">
+          Additional ideas and design from{" "}
+          {IDEA_CREDITS.map((c, i) => (
+            <span key={c.handle}>
+              {i > 0 && (i === IDEA_CREDITS.length - 1 ? " and " : ", ")}
+              <a
+                href={c.url}
+                target="_blank"
+                rel="noreferrer noopener"
+                className={LINK}
+              >
+                {c.handle}
+              </a>
+            </span>
+          ))}
+          {"."}
+        </p>
+      )}
+
       {/*
         Placed under the disclaimer that admits dates can be wrong, because that
         paragraph is where a reader who has just found one is looking. The bug