fix: use static mode for completed markdown to prevent render delay

After the ORPC migration, async event boundaries let React deprioritize
Streamdown's useTransition() indefinitely, causing 10+ second delays
for plan body rendering.

Fix: Set mode='static' for completed content (parseIncompleteMarkdown=false)
to bypass useTransition() and render immediately. This aligns with
Streamdown's intended API usage.

Author: ethanndickson

bun.lock

@@ -1,5 +1,6 @@
 {
   "lockfileVersion": 1,
+  "configVersion": 0,
   "workspaces": {
     "": {
       "name": "mux",

src/browser/components/Messages/MarkdownCore.tsx

@@ -62,6 +62,9 @@ export const MarkdownCore = React.memo<MarkdownCoreProps>(
           remarkPlugins={REMARK_PLUGINS}
           rehypePlugins={REHYPE_PLUGINS}
           parseIncompleteMarkdown={parseIncompleteMarkdown}
+          // Use "static" mode for completed content to bypass useTransition() deferral.
+          // After ORPC migration, async event boundaries let React deprioritize transitions indefinitely.
+          mode={parseIncompleteMarkdown ? "streaming" : "static"}
           className="space-y-2" // Reduce from default space-y-4 (16px) to space-y-2 (8px)
           controls={{ table: false, code: true, mermaid: true }} // Disable table copy/download, keep code/mermaid controls
         >