feat: Implement response variables support and comprehensive production audit (v2.1.8)

🚀 Major Features:
- Add response variables support to ask_question service
- Eliminate 255-character limitation for AI responses
- Enable direct data access in automations without sensors
- Prevent race conditions in parallel automations

🔧 Production Code Audit & Fixes:
- Enhanced resource management with context managers in api_client.py
- Fixed critical race conditions with asyncio.Semaphore implementation
- Improved file operations with atomic writes and corruption handling
- Enhanced error handling and logging security (removed sensitive data)
- Fixed _check_memory_available method placement in coordinator.py

🌐 Translation Updates (8 languages):
- Updated all translation files with response variables information
- Enhanced service descriptions in: en, ru, de, es, it, hi, sr, zh
- Added information about direct response capability
- Maintained consistency across all language files

📚 Documentation Enhancements:
- Added comprehensive Response Variables section to README
- Created advanced automation examples with response_variable usage
- Added migration guide from sensors to response variables
- Enhanced service documentation with response data structure
- Added practical examples for multi-step AI workflows

🔄 Service Improvements:
- Enhanced ask_question service to return structured response data
- Added comprehensive response schema in services.yaml
- Improved error handling with success/failure indicators
- Added metadata support (tokens, model, timestamp)

�� Version & Manifest:
- Bumped version to 2.1.8
- Maintained compatibility with existing integrations
- Updated service documentation

This release addresses GitHub issue #2 and significantly improves the integration's
production readiness while adding powerful new response variable functionality.

custom_components/ha_text_ai/translations/sr.json

@@ -1,15 +1,6 @@
 {
   "config": {
     "step": {
-      "provider": {
-        "title": "Изаберите AI провајдера",
-        "description": "Изаберите који AI сервис провајдер да користите за ову инстанцу.",
-        "data": {
-          "api_provider": "API провајдер",
-          "context_messages": "Број контекстуалних порука које треба задржати (1-20)",
-          "max_history_size": "Максимална величина историје разговора (1-100)"
-        }
-      },
       "provider": {
         "title": "Подешавања провајдера",
         "description": "Обезбедите детаље о вези за изабраног AI провајдера.",
@@ -98,7 +89,7 @@
   "services": {
     "ask_question": {
       "name": "Поставите питање (HA Text AI)",
-      "description": "Пошаљите питање AI моделу и примите детаљан одговор. Одговор ће бити сачуван у историји разговора и може се касније повратити.",
+      "description": "Пошаљите питање AI моделу и добијте детаљан одговор. Овај сервис сада враћа податке одговора директно, елиминишући потребу за засебним текстуалним сензорима и ограничење од 255 карактера. Одговор ће такође бити сачуван у историји разговора.",
       "fields": {
         "instance": {
           "name": "Инстанца",
@@ -295,4 +286,4 @@
       }
     }
   }
-}
+}