feat: multiple improvements, additions, vibin'

functions/nvm_extract_version.fish

@@ -0,0 +1,51 @@
+function nvm_extract_version -a file_path -d "Extract Node.js version from various file formats"
+    if test -z "$file_path"
+        return 1
+    end
+
+    set -l file_name (basename "$file_path")
+    set -l version_info (string split ':' "$file_path")
+    set -l actual_file $version_info[1]
+    set -l format $version_info[2]
+
+    if not test -f "$actual_file" -a -r "$actual_file"
+        return 1
+    end
+
+    switch "$format"
+        case engines.node
+            # Extract from package.json engines.node field
+            if command -q jq
+                set -l version (jq -r '.engines.node // empty' "$actual_file" 2>/dev/null)
+                if test -n "$version" -a "$version" != null
+                    # Handle version ranges - extract first valid version
+                    set version (string replace -r '^[^0-9]*([0-9]+\.?[0-9]*\.?[0-9]*).*' '$1' "$version")
+                    echo "$version"
+                    return 0
+                end
+            end
+        case nodejs
+            # Extract from .tool-versions nodejs line
+            set -l version (grep '^nodejs ' "$actual_file" | cut -d' ' -f2 | string trim)
+            if test -n "$version"
+                echo "$version"
+                return 0
+            end
+        case '*'
+            # Standard .nvmrc or .node-version file
+            set -l version (cat "$actual_file" | string trim)
+            if test -n "$version"
+                # Handle nvm aliases
+                switch "$version"
+                    case 'lts/*' lts latest stable node
+                        if command -q nvm
+                            set version (nvm version-remote "$version" 2>/dev/null | string replace 'v' '')
+                        end
+                end
+                echo "$version"
+                return 0
+            end
+    end
+
+    return 1
+end