fix: ensure dbc.exe is cached and sidecar write is guarded on Windows

- Add ~/.local/bin/dbc.exe to cache path so Windows binary is restored on cache hit
- Guard empty $installDir in cache-hit PATH step with Write-Error diagnostic
- Move sidecar write in install-windows.ps1 to after dbc --version succeeds so only a verified install location is recorded

Author: zeroshade

action.yml

@@ -52,6 +52,7 @@ runs:
         # Missing paths are silently ignored by the cache action
         path: |
           ~/.local/bin/dbc
+          ~/.local/bin/dbc.exe
           ~/.local/bin/dbc-install-dir.txt
           ~/Library/Application Support/dbc
           ${{ runner.temp }}/dbc
@@ -86,7 +87,11 @@ runs:
         } else {
             $installDir = Join-Path $env:USERPROFILE ".local\bin"
         }
-        $installDir | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+        if ($installDir) {
+            $installDir | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
+        } else {
+            Write-Error "dbc-install-dir.txt is empty; cannot add dbc to PATH"
+        }
 
     - name: Get installed version
       id: install

install-windows.ps1

@@ -63,7 +63,11 @@ try {
         $actualDbcDir | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
     }
 
+    # Output version for verification
+    dbc --version
+
     # Save actual install path so cache-hit runs use the verified location.
+    # Written after dbc --version succeeds to guarantee it records a working install.
     # Always written to ~\.local\bin\dbc-install-dir.txt regardless of $actualDbcDir,
     # consistent with the cache-restore step that reads from that fixed path.
     # Guarded by $env:GITHUB_PATH to skip during local debugging outside GitHub Actions.
@@ -72,9 +76,6 @@ try {
         $actualDbcDir | Out-File -FilePath (Join-Path $env:USERPROFILE ".local\bin\dbc-install-dir.txt") -Encoding utf8
     }
 
-    # Output version for verification
-    dbc --version
-
     Write-Host "dbc CLI installed successfully"
 }
 catch {