[mercury] update ch-chat styles (#395)

* `[ch-chat]`add required files to use `mercury-code-render`

* Add showcase page

* little improvements on `ch-chat`

* update showcase files

Author: bsastregx

packages/mercury/showcase/all.css

@@ -0,0 +1,59 @@
+import { h } from "./index-29553cff.js";
+
+const copy = text => () => navigator.clipboard.writeText(text);
+export const mercuryCodeRender = copyButtonAccessibleName => options =>
+  h(
+    "div",
+    { class: "code-block-container" },
+    h(
+      "div",
+      { class: "code-block-header" },
+      h("button", {
+        "aria-label": copyButtonAccessibleName,
+        title: copyButtonAccessibleName,
+        class: "button-copy-code",
+        type: "button",
+        onClick: copy(options.plainText)
+      })
+    ),
+    h("ch-code", {
+      language: options.language,
+      lastNestedChildClass: options.lastNestedChildClass,
+      value: options.plainText
+    })
+  );
+export const mercuryChatMessageRender = theme => messageModel =>
+  messageModel.role === "assistant" && messageModel.status === "waiting"
+    ? [
+        h("span", { part: "message__processing" }, messageModel.content),
+        h("div", {
+          class: "processing-animation",
+          part: "processing-animation"
+        })
+      ]
+    : [
+        h(
+          "span",
+          { part: `message__role ${messageModel.role}` },
+          messageModel.role === "user" ? "You" : "GeneXus Code Fixer"
+        ),
+        h(
+          "time",
+          { dateTime: messageModel.metadata, part: "message__time" },
+          messageModel.metadata
+        ),
+        messageModel.role === "user"
+          ? h("span", { part: "message__content user" }, messageModel.content)
+          : h("ch-markdown-viewer", {
+              part:
+                messageModel.role === "assistant" &&
+                (messageModel.status === "complete" || !messageModel.status) &&
+                !messageModel.parts
+                  ? `message__content no-error`
+                  : "message__content",
+              theme: theme,
+              showIndicator: false,
+              renderCode: mercuryCodeRender("Copy code"),
+              value: messageModel.content
+            })
+      ];