feat(perm): 添加会话权限模式管理功能

实现会话权限模式管理功能，包括：
1. 在 pty_process 中定义三种权限模式标志
2. 添加 /perm 命令用于修改会话权限模式
3. 新增 run_command 工具用于执行 bot 控制命令
4. 在会话管理中支持权限模式设置
5. 添加完整的测试用例和文档说明

tests/features/commands/perm.feature

@@ -0,0 +1,70 @@
+Feature: /perm command — change session permission mode
+
+  Background:
+    Given user "user_abc123" is sending commands
+
+  Scenario: No args shows usage
+    When user sends "/perm"
+    Then reply contains "Usage"
+    And reply contains "bypass"
+    And reply contains "accept"
+    And reply contains "plan"
+
+  Scenario: Set active session to accept mode
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    When user sends "/perm accept"
+    Then reply contains "accept"
+    And reply contains "sess01"
+    And session "sess01" has permission mode "acceptEdits"
+
+  Scenario: Set active session to plan mode
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    When user sends "/perm plan"
+    Then reply contains "plan"
+    And session "sess01" has permission mode "plan"
+
+  Scenario: Set active session back to bypass
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    When user sends "/perm bypass"
+    Then reply contains "bypass"
+    And session "sess01" has permission mode "bypassPermissions"
+
+  Scenario: Unknown mode returns error
+    Given user has session "sess01" in "/tmp/proj1"
+    And active session is "sess01"
+    When user sends "/perm turbo"
+    Then reply contains "Unknown mode"
+
+  Scenario: No active session returns error
+    Given no active session for user "user_abc123"
+    When user sends "/perm accept"
+    Then reply contains "No active session"
+
+  Scenario: Set permission on specific conv_id
+    Given user has session "sess01" in "/tmp/proj1"
+    And user has session "sess02" in "/tmp/proj2"
+    And active session is "sess01"
+    When user sends "/perm plan sess02"
+    Then reply contains "sess02"
+    And session "sess02" has permission mode "plan"
+
+  Scenario: Cannot change permission of another user's session
+    Given session "sess01" in "/tmp/proj1" belongs to user "other_user"
+    When user sends "/perm accept sess01"
+    Then reply contains "another user"
+
+  Scenario: New session with --perm accept
+    When user sends "/new myproject --perm accept"
+    Then reply contains "accept"
+    And session manager has 1 session for user "user_abc123"
+
+  Scenario: New session with --perm plan
+    When user sends "/new myproject --perm plan"
+    Then reply contains "plan"
+
+  Scenario: New session with invalid --perm
+    When user sends "/new myproject --perm turbo"
+    Then reply contains "Invalid"

tests/step_defs/common_steps.py

@@ -143,6 +143,15 @@ def check_no_active_session(user_id):
     assert agent._active_conv.get(user_id) is None
 
 
+@then(parsers.parse('session "{conv_id}" has permission mode "{mode}"'))
+def check_session_perm_mode(conv_id, mode):
+    from agent.manager import manager
+    session = manager._sessions.get(conv_id)
+    assert session is not None, f"Session {conv_id!r} not found"
+    assert session.permission_mode == mode, \
+        f"Expected permission_mode={mode!r}, got {session.permission_mode!r}"
+
+
 # ── Then: mode state ─────────────────────────────────────────────────────────
 
 @then(parsers.parse('passthrough mode is enabled for user "{user_id}"'))

tests/step_defs/test_commands.py

@@ -20,6 +20,7 @@ scenarios(
     "../features/commands/tasks.feature",
     "../features/commands/nodes.feature",
     "../features/commands/help.feature",
+    "../features/commands/perm.feature",
 )