fix: Windows auto-update path detection and install function support (#404)

* fix: Windows auto-update path detection and add install function support

- Fix Windows path inconsistency: check ~/.config first, then %APPDATA%
- Add actual update installation via runBunInstall when autoUpdate=true
- Check both Windows config locations for comprehensive detection

Closes #402

* fix: address review feedback on error logging and message clarity

- Update misleading log message to clarify fallback behavior
- Serialize error object before logging to prevent {} serialization

---------

Co-authored-by: sisyphus-dev-ai <sisyphus-dev-ai@users.noreply.github.com>

src/hooks/auto-update-checker/checker.ts

@@ -9,7 +9,10 @@ import {
   INSTALLED_PACKAGE_JSON,
   USER_OPENCODE_CONFIG,
   USER_OPENCODE_CONFIG_JSONC,
+  USER_CONFIG_DIR,
+  getWindowsAppdataDir,
 } from "./constants"
+import * as os from "node:os"
 import { log } from "../../shared/logger"
 
 export function isLocalDevMode(directory: string): boolean {
@@ -23,12 +26,32 @@ function stripJsonComments(json: string): string {
 }
 
 function getConfigPaths(directory: string): string[] {
-  return [
+  const paths = [
     path.join(directory, ".opencode", "opencode.json"),
     path.join(directory, ".opencode", "opencode.jsonc"),
     USER_OPENCODE_CONFIG,
     USER_OPENCODE_CONFIG_JSONC,
   ]
+  
+  if (process.platform === "win32") {
+    const crossPlatformDir = path.join(os.homedir(), ".config")
+    const appdataDir = getWindowsAppdataDir()
+    
+    if (appdataDir) {
+      const alternateDir = USER_CONFIG_DIR === crossPlatformDir ? appdataDir : crossPlatformDir
+      const alternateConfig = path.join(alternateDir, "opencode", "opencode.json")
+      const alternateConfigJsonc = path.join(alternateDir, "opencode", "opencode.jsonc")
+      
+      if (!paths.includes(alternateConfig)) {
+        paths.push(alternateConfig)
+      }
+      if (!paths.includes(alternateConfigJsonc)) {
+        paths.push(alternateConfigJsonc)
+      }
+    }
+  }
+  
+  return paths
 }
 
 export function getLocalDevPath(directory: string): string | null {