feat: 添加测试框架及功能测试用例

test: 实现BDD测试框架及功能测试
docs: 添加测试配置文件及文档
refactor: 重构命令处理逻辑以支持测试

tests/features/commands/status.feature

@@ -0,0 +1,40 @@
+Feature: /status command — list sessions and current mode
+
+  Background:
+    Given user "user_abc123" is sending commands
+
+  Scenario: No sessions returns empty message
+    When user sends "/status"
+    Then reply contains "No active sessions"
+
+  Scenario: Shows session list
+    Given user has session "sess01" in "/tmp/proj1"
+    And user has session "sess02" in "/tmp/proj2"
+    When user sends "/status"
+    Then reply contains "sess01"
+    And reply contains "sess02"
+
+  Scenario: Shows active marker on current session
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    When user sends "/status"
+    Then reply contains "→"
+
+  Scenario: Shows current mode as Smart by default
+    Given user has session "sess01" in "/tmp/proj1"
+    When user sends "/status"
+    Then reply contains "Smart"
+
+  Scenario: Shows Direct mode after /direct
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    And direct mode is enabled for user "user_abc123"
+    When user sends "/status"
+    Then reply contains "Direct"
+
+  Scenario: Sends card when chat_id is set
+    Given user has session "sess01" in "/tmp/proj1"
+    And the current chat_id is "chat_xyz"
+    When user sends "/status"
+    Then a sessions card is sent to chat "chat_xyz"
+    And text reply is empty