fix: show dyad-command buttons within assistant responses instead of hiding tags (#1421) (#1432)

### Problem
Users were confused because `<dyad-command>` tags were being hidden,
making it unclear what actions were available.

### Solution
Render dyad-command tags as visible buttons, so users can see and
interact with available commands (e.g., "restart").

Closes #1421
    
<!-- This is an auto-generated description by cubic. -->
---

## Summary by cubic
Show dyad-command tags as visible buttons in assistant responses so
users can see and trigger actions (e.g., restart). Closes #1421.

- **Bug Fixes**
  - Render dyad-command tags to buttons in DyadMarkdownParser.
  - Export mapActionToButton from ChatInput for reuse.
  - Support id/action/path attributes; safely no-op if parsing fails.

<!-- End of auto-generated description by cubic. -->

src/components/chat/ChatInput.tsx

@@ -556,7 +556,7 @@ function KeepGoingButton() {
   );
 }
 
-function mapActionToButton(action: SuggestedAction) {
+export function mapActionToButton(action: SuggestedAction) {
   switch (action.id) {
     case "summarize-in-new-chat":
       return <SummarizeInNewChatButton />;

src/components/chat/DyadMarkdownParser.tsx

@@ -22,6 +22,8 @@ import { DyadMcpToolResult } from "./DyadMcpToolResult";
 import { DyadWebSearchResult } from "./DyadWebSearchResult";
 import { DyadWebSearch } from "./DyadWebSearch";
 import { DyadRead } from "./DyadRead";
+import { mapActionToButton } from "./ChatInput";
+import { SuggestedAction } from "@/lib/schemas";
 
 interface DyadMarkdownParserProps {
   content: string;
@@ -498,7 +500,12 @@ function renderCustomTag(
       return null;
 
     case "dyad-command":
-      // Don't render anything for dyad-command
+      if (attributes.type) {
+        const action = {
+          id: attributes.type,
+        } as SuggestedAction;
+        return <>{mapActionToButton(action)}</>;
+      }
       return null;
 
     default: