refactor: remove redundant custom-strings validation and global variable

Remove duplicate validation in cli.ts since comprehensive validation already exists in loadCustomStrings(). Also eliminate unnecessary customStrings global variable by using customStringsData directly.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: strickvl

src/node/cli.ts

@@ -466,20 +466,6 @@ export const parse = (
     throw new Error("--cert-key is missing")
   }
 
-  // Validate custom-strings flag
-  if (args["custom-strings"]) {
-    try {
-      // First try to parse as JSON directly
-      JSON.parse(args["custom-strings"])
-    } catch (jsonError) {
-      // If JSON parsing fails, check if it's a valid file path
-      if (!args["custom-strings"].startsWith("{") && !args["custom-strings"].startsWith("[")) {
-        // Assume it's a file path - validation will happen later when the file is read
-      } else {
-        throw error(`--custom-strings contains invalid JSON: ${jsonError instanceof Error ? jsonError.message : String(jsonError)}`)
-      }
-    }
-  }
 
   logger.debug(() => [`parsed ${opts?.configFile ? "config" : "command line"}`, field("args", redactArgs(args))])
 

src/node/i18n/index.ts

@@ -24,7 +24,6 @@ const defaultResources = {
   },
 }
 
-let customStrings: Record<string, any> = {}
 
 export async function loadCustomStrings(customStringsArg?: string): Promise<void> {
   if (!customStringsArg) {
@@ -43,15 +42,13 @@ export async function loadCustomStrings(customStringsArg?: string): Promise<void
       customStringsData = JSON.parse(fileContent)
     }
 
-    customStrings = customStringsData
-
     // Re-initialize i18next with merged resources
     const mergedResources = Object.keys(defaultResources).reduce((acc, lang) => {
       const langKey = lang as keyof typeof defaultResources
       acc[langKey] = {
         translation: {
           ...defaultResources[langKey].translation,
-          ...customStrings,
+          ...customStringsData,
         },
       }
       return acc