feat(event-notifier): improve environment variable handling

- Fix deserialization error when parsing config from environment variables
- Add proper array format support for adapters configuration
- Update environment variable examples with correct format
- Improve documentation for configuration loading
- Implement helper functions for environment variable validation

This change fixes the "invalid type: map, expected a sequence" error
by ensuring proper formatting of array-type fields in environment variables.

crates/event-notifier/examples/.env-zh.example

@@ -0,0 +1,28 @@
+# ===== 全局配置 =====
+NOTIFIER__STORE_PATH=/var/log/event-notification
+NOTIFIER__CHANNEL_CAPACITY=5000
+
+# ===== 适配器配置（数组格式） =====
+# Webhook 适配器（索引 0）
+NOTIFIER__ADAPTERS_0__type=Webhook
+NOTIFIER__ADAPTERS_0__endpoint=http://127.0.0.1:3000/webhook
+NOTIFIER__ADAPTERS_0__auth_token=your-auth-token
+NOTIFIER__ADAPTERS_0__max_retries=3
+NOTIFIER__ADAPTERS_0__timeout=50
+NOTIFIER__ADAPTERS_0__custom_headers__x_custom_server=value
+NOTIFIER__ADAPTERS_0__custom_headers__x_custom_client=value
+
+# Kafka 适配器（索引 1）
+NOTIFIER__ADAPTERS_1__type=Kafka
+NOTIFIER__ADAPTERS_1__brokers=localhost:9092
+NOTIFIER__ADAPTERS_1__topic=notifications
+NOTIFIER__ADAPTERS_1__max_retries=3
+NOTIFIER__ADAPTERS_1__timeout=60
+
+# MQTT 适配器（索引 2）
+NOTIFIER__ADAPTERS_2__type=Mqtt
+NOTIFIER__ADAPTERS_2__broker=mqtt.example.com
+NOTIFIER__ADAPTERS_2__port=1883
+NOTIFIER__ADAPTERS_2__client_id=event-notifier
+NOTIFIER__ADAPTERS_2__topic=events
+NOTIFIER__ADAPTERS_2__max_retries=3