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/qwen.go

@@ -73,7 +73,7 @@ func (p *QwenPlugin) Uninstall(agentID string) error {
 	if err != nil {
 		return err
 	}
-	runtimeRoot, err := qwenRuntimeRoot()
+	runtimeRoot, err := AgentRuntimeRoot()
 	if err != nil {
 		return err
 	}
@@ -104,7 +104,7 @@ func (p *QwenPlugin) Status() (PluginStatus, error) {
 		return status, err
 	}
 	status.ConfigPath = sources.user.filePath
-	runtimeRoot, err := qwenRuntimeRoot()
+	runtimeRoot, err := AgentRuntimeRoot()
 	if err != nil {
 		return status, err
 	}