feat: typewriter-эффект в логотипе dedinit() — темы блога в скобках

- layouts/partials/extend_footer.html: инлайн-скрипт (печать/пауза/стирание/мигание, prefers-reduced-motion, слова из [params.typewriter])
- assets/css/extended/typewriter.css: блочный мигающий курсор
- hugo.toml: [params.typewriter] words
- openspec/changes/header-typewriter: proposal/design/specs/tasks

Без зависимостей (Alpine не нужен), тема не модифицируется.

assets/css/extended/typewriter.css

@@ -0,0 +1,30 @@
+/* dedinit() typewriter — animated blog topics inside the logo parens.
+   Progressive enhancement: pure CSS cursor blink, JS only drives the text. */
+
+#dedinit-typewriter {
+    display: inline-block;
+    white-space: nowrap;       /* never wrap the typed word */
+    min-width: 0.5ch;          /* keeps parens from collapsing when empty */
+    text-align: left;
+}
+
+#dedinit-typewriter .tw-cursor {
+    display: inline-block;
+    width: 0.55ch;
+    height: 1.05em;
+    margin-inline-start: 0.15ch;
+    background: currentColor;  /* follows light/dark text color */
+    vertical-align: -0.12em;
+    animation: tw-blink 1s steps(1) infinite;
+}
+
+@keyframes tw-blink {
+    50% { opacity: 0; }
+}
+
+@media (prefers-reduced-motion: reduce) {
+    #dedinit-typewriter .tw-cursor {
+        animation: none;       /* static cursor, no blink */
+        opacity: 0.6;
+    }
+}