fix: workflow_callトリガーを追加して再利用可能なワークフローに修正

- test-japanese-tts.yml にworkflow_callトリガーを追加
- test-multilingual-tts.yml にworkflow_callトリガーを追加
- これにより他のワークフローから呼び出し可能に

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ayutaz

.github/workflows/test-japanese-tts.yml

@@ -16,6 +16,10 @@ on:
       - '.github/workflows/test-japanese-tts.yml'
       - '.github/workflows/build-piper.yml'
   workflow_dispatch:
+  workflow_call:
+    permissions:
+      contents: read
+      packages: read
 
 jobs:
   # Build piper for all platforms

.github/workflows/test-multilingual-tts.yml

@@ -32,6 +32,21 @@ on:
           - basic
           - comprehensive
           - performance
+  workflow_call:
+    inputs:
+      languages:
+        description: 'Languages to test (comma-separated, e.g., en_US,de_DE,fr_FR)'
+        required: false
+        default: 'en_US,de_DE,fr_FR,es_ES,zh_CN'
+        type: string
+      test_type:
+        description: 'Test type'
+        required: false
+        default: 'basic'
+        type: string
+    permissions:
+      contents: read
+      packages: read
 
 env:
   # HuggingFace model repository