fix: preserve full error stacks in desktop renderer logs

Electron's console-message event only surfaces {level, message, line, sourceId}
without the stack, so uncaught errors showed up as 'line 1028 of chunk-*.js'
(SolidJS's rethrow site) with no way to find the real origin. Attach
window error and unhandledrejection listeners that log the full stack via
console.error, and reshape the main-process log line so newlines in the
stack survive instead of being JSON-escaped into one unreadable blob.

packages/desktop-electron/src/main/index.ts

@@ -258,16 +258,20 @@ async function initialize() {
 
 function wireWindowDiagnostics(win: BrowserWindow, label: string) {
   win.webContents.on("console-message", (_event, level, message, line, sourceId) => {
-    const payload = { level, message, line, sourceId }
+    // Render `message` as a block so multi-line stack traces survive; the
+    // previous shape stuffed the message into a JSON object which escaped
+    // `\n` and made stacks unreadable.
+    const location = sourceId ? ` [${sourceId}:${line}]` : ""
+    const text = `${label} renderer${location}\n${message}`
     if (level >= 3) {
-      logger.error(`${label} renderer console`, payload)
+      logger.error(text)
       return
     }
     if (level >= 2) {
-      logger.warn(`${label} renderer console`, payload)
+      logger.warn(text)
       return
     }
-    logger.log(`${label} renderer console`, payload)
+    logger.log(text)
   })
 
   win.webContents.on("did-fail-load", (_event, errorCode, errorDescription, validatedURL, isMainFrame) => {

packages/desktop-electron/src/renderer/index.tsx

@@ -1,5 +1,25 @@
 // @refresh reload
 
+// Install global error listeners before any other module runs so that
+// uncaught errors and rejected promises reach the main process with their
+// full stacks intact. Electron's `console-message` event only forwards the
+// rethrow site, so without these we lose the originating frame.
+window.addEventListener("error", (event) => {
+  const err = event.error
+  const stack = err instanceof Error ? err.stack : null
+  console.error(
+    "[renderer uncaught]",
+    stack ?? event.message,
+    stack ? "" : `${event.filename}:${event.lineno}:${event.colno}`,
+  )
+})
+
+window.addEventListener("unhandledrejection", (event) => {
+  const reason = event.reason
+  const stack = reason instanceof Error ? reason.stack : null
+  console.error("[renderer unhandled rejection]", stack ?? reason)
+})
+
 import {
   ACCEPTED_FILE_EXTENSIONS,
   ACCEPTED_FILE_TYPES,