feat(version-detection): support version_command for tools without PATH binaries

Problem:
- ruby-build fails with "version unchanged" after successful git update
- Installed as rbenv plugin at ~/.rbenv/plugins/ruby-build (not in PATH)
- Detection only works for binaries found via which/PATH
- github_clone installer updates git repo but version detection fails

Changes:
- Add version_command field to ruby-build catalog
  - Extracts version from git commit message
  - Command: cd ~/.rbenv/plugins/ruby-build && git log -1 --format='%s' | grep -oP 'ruby-build \\K[0-9]+'
- Modify cli_audit/detection.py audit_tool_installation()
  - Check version_command independently when no binary path found
  - Add fallback version detection for non-PATH tools
  - Mark path as "<version_command>" for install_method tracking

Resolution:
- ruby-build: installed 20251023 === latest 20251023
- Version detection working for plugin-based github_clone tools
- Upgrade warnings no longer trigger incorrectly

Technical details:
- version_command executed via shell when binary not in PATH
- Supports git-based versioning, file parsing, custom commands
- Catalog-driven: works for any tool with version_command field

Author: CybotTM

catalog/ruby-build.json

@@ -6,8 +6,9 @@
   "github_repo": "rbenv/ruby-build",
   "binary_name": "ruby-build",
   "clone_path": "~/.rbenv/plugins/ruby-build",
-  "notes": "Installs as rbenv plugin. Requires rbenv to be installed first."
-  ,"guide": {
+  "version_command": "cd ~/.rbenv/plugins/ruby-build && git log -1 --format='%s' | grep -oP 'ruby-build \\K[0-9]+'",
+  "notes": "Installs as rbenv plugin. Requires rbenv to be installed first.",
+  "guide": {
     "display_name": "ruby-build",
     "install_action": "install",
     "order": 31

cli_audit/detection.py

@@ -315,6 +315,13 @@ def audit_tool_installation(
                 num = extract_version_number(line)
                 tuples.append((num, line, path))
 
+    # If no paths found but version_command exists, try standalone version detection
+    if not tuples and version_command:
+        line = get_version_line("", tool_name, version_flag, version_command)
+        if line:
+            num = extract_version_number(line)
+            tuples.append((num, line, "<version_command>"))
+
     if not tuples:
         return ("", "X", "", "")
 
@@ -323,6 +330,11 @@ def audit_tool_installation(
         return ("", "X", "", "")
 
     version_num, version_line, path = chosen
-    install_method = detect_install_method(path, tool_name)
+
+    # Handle version_command detection (no physical path)
+    if path == "<version_command>":
+        install_method = "version_command"
+    else:
+        install_method = detect_install_method(path, tool_name)
 
     return (version_num, version_line, path, install_method)