feat: localchat, a Go + Templ + HTMX chat app for local Gemma models

Streams replies over SSE from any OpenAI-compatible server (oMLX,
llama.cpp, Ollama, ...). Single binary that can install itself as an
OS service; docker compose bundles llama.cpp + Gemma 4 E2B.

internal/web/static/app.js

@@ -0,0 +1,39 @@
+// Small UX touches on top of HTMX: Enter to send, auto-growing textarea,
+// clearing the input after sending, and keeping the newest message in view.
+(() => {
+  const form = document.getElementById("composer");
+  const input = form.querySelector("textarea");
+  const messages = document.getElementById("messages");
+
+  const grow = () => {
+    input.style.height = "auto";
+    input.style.height = input.scrollHeight + "px";
+  };
+  const nearBottom = () =>
+    messages.scrollHeight - messages.scrollTop - messages.clientHeight < 120;
+  const scrollDown = () => (messages.scrollTop = messages.scrollHeight);
+
+  input.addEventListener("input", grow);
+  input.addEventListener("keydown", (e) => {
+    if (e.key === "Enter" && !e.shiftKey && !e.isComposing) {
+      e.preventDefault();
+      if (input.value.trim()) form.requestSubmit();
+    }
+  });
+
+  form.addEventListener("htmx:afterRequest", (e) => {
+    if (e.detail.successful) {
+      form.reset();
+      grow();
+      scrollDown();
+    }
+  });
+
+  // Follow streaming tokens, unless the user scrolled up to read.
+  let follow = true;
+  messages.addEventListener("scroll", () => (follow = nearBottom()));
+  document.body.addEventListener("htmx:sseMessage", () => follow && scrollDown());
+  document.body.addEventListener("htmx:afterSwap", () => follow && scrollDown());
+
+  scrollDown();
+})();