fix(cache): use user-writable ~/.serve.zone/dcrouter for TsmDB and centralize data path logic

ts/cache/classes.cachedb.ts

@@ -1,11 +1,12 @@
 import * as plugins from '../plugins.js';
 import { logger } from '../logger.js';
+import { defaultTsmDbPath } from '../paths.js';
 
 /**
  * Configuration options for CacheDb
  */
 export interface ICacheDbOptions {
-  /** Base storage path for TsmDB data (default: /etc/dcrouter/tsmdb) */
+  /** Base storage path for TsmDB data (default: ~/.serve.zone/dcrouter/tsmdb) */
   storagePath?: string;
   /** Database name (default: dcrouter) */
   dbName?: string;
@@ -29,7 +30,7 @@ export class CacheDb {
 
   constructor(options: ICacheDbOptions = {}) {
     this.options = {
-      storagePath: options.storagePath || '/etc/dcrouter/tsmdb',
+      storagePath: options.storagePath || defaultTsmDbPath,
       dbName: options.dbName || 'dcrouter',
       debug: options.debug || false,
     };