chore(go): audit providers kimi grok qwen letta

Move Kimi, Grok, and Qwen onto managed_runtime.go and shell_command.go;
share the encoded and shell command builders and the quoted Windows
legacy parser with Droid; split managed_changes.go; dedupe Letta's hook
entry filtering and stop swallowing settings read errors.

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

cmd/elydora/plugins/grok_io.go

@@ -85,32 +85,17 @@ func writeGrokChanges(
 	agentDirectory string,
 	hooksDirectory string,
 ) error {
-	hasChanges := false
-	for _, change := range changes {
-		if change != nil {
-			hasChanges = true
-			break
-		}
-	}
-	if !hasChanges {
+	if !hasFileChanges(changes) {
 		return nil
 	}
-	if agentDirectory != "" {
-		if err := EnsurePrivateDirectory(runtimeRoot); err != nil {
-			return err
-		}
-		if err := EnsurePrivateDirectory(agentDirectory); err != nil {
-			return err
-		}
-	}
 	if err := ensureManagedDirectory(
 		filepath.Dir(hooksDirectory),
 		"Grok home directory",
 	); err != nil {
 		return err
 	}
-	if err := ensureManagedDirectory(hooksDirectory, "Grok hooks directory"); err != nil {
-		return err
-	}
-	return writeChanges(changes, label, rename)
+	return writeManagedChanges(
+		changes, label, rename, runtimeRoot, agentDirectory,
+		hooksDirectory, "Grok hooks directory",
+	)
 }