Fix: Clarify installation options and warn about copied files

- README: Add Option A (direct include) as recommended method
- README: Add Option B (copy) with warning about manual updates
- install.sh: Detect direct include vs copied files
- README: Add troubleshooting for 'Error loading template' after update

The root cause: Moonraker updates the repo, but copied files in
~/printer_data/config/calibration/ don't get updated automatically.

Solution: Use direct include [include open4neptune-new/calibration/*.cfg]
so files are always loaded from the repo.

install.sh

@@ -22,9 +22,19 @@ echo ""
 # Check if calibration folder exists
 if [ -d "$SCRIPT_DIR/calibration" ]; then
     echo "✓ Found calibration folder"
-    echo "  Copying to config directory..."
-    cp -r "$SCRIPT_DIR/calibration" "$CONFIG_DIR/"
-    echo "  ✓ Calibration macros installed"
+    
+    # Check if using direct include (recommended) or copied files
+    if [ -d "$CONFIG_DIR/open4neptune-new/calibration" ]; then
+        echo "  ℹ Using direct include from repo (recommended!)"
+        echo "    No copy needed - files update automatically"
+    else
+        echo "  Copying to config directory..."
+        cp -r "$SCRIPT_DIR/calibration" "$CONFIG_DIR/"
+        echo "  ✓ Calibration macros installed"
+        echo "  ⚠️ Note: Copied files won't auto-update!"
+        echo "    Consider switching to direct include:"
+        echo "    [include open4neptune-new/calibration/*.cfg]"
+    fi
 else
     echo "✗ Calibration folder not found"
 fi