chore(go): audit providers claudecode codex cursor gemini

Add managed_runtime.go (paths, config validation, identity, runtime file
changes, status checks) and shell_command.go (quoting, PowerShell
encoding, command parsing) and move the four providers onto them.

Claude-Session: https://claude.ai/code/session_01Agoc9bRVE9KL7mmWtey9Vq

cmd/elydora/plugins/grok_command.go

@@ -41,7 +41,7 @@ func buildGrokCommand(runtimePath, scriptPath string) (string, error) {
 		)
 	}
 	if runtime.GOOS == "windows" {
-		return codexWindowsCommand(runtimePath, scriptPath), nil
+		return encodedWindowsCommand(runtimePath, scriptPath), nil
 	}
 	return quotePOSIXArgument(runtimePath) + " " + quotePOSIXArgument(scriptPath), nil
 }
@@ -85,10 +85,10 @@ func parseGrokLegacyWindowsCommand(command string) (string, string, bool) {
 }
 
 func parseGrokCommand(command string) (string, string, bool) {
-	if runtimePath, scriptPath, ok := parseCodexPOSIXCommand(command); ok {
+	if runtimePath, scriptPath, ok := parsePOSIXCommand(command); ok {
 		return runtimePath, scriptPath, true
 	}
-	if runtimePath, scriptPath, ok := parseCodexWindowsCommand(command); ok {
+	if runtimePath, scriptPath, ok := parseEncodedWindowsCommand(command); ok {
 		return runtimePath, scriptPath, true
 	}
 	return parseGrokLegacyWindowsCommand(command)