fix: add from __future__ import annotations across codebase

Ensure all modules using PEP 604 union syntax (X | Y) include
the future annotations import for Python <3.10 compatibility.
While the project requires >=3.11, this avoids import-time
TypeErrors when running tests on older interpreters.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

nanobot/agent/context.py

@@ -1,5 +1,7 @@
 """Context builder for assembling agent prompts."""
 
+from __future__ import annotations
+
 import base64
 import mimetypes
 import platform

nanobot/agent/subagent.py

@@ -1,5 +1,7 @@
 """Subagent manager for background task execution."""
 
+from __future__ import annotations
+
 import asyncio
 import json
 import uuid

nanobot/agent/tools/base.py

@@ -1,5 +1,7 @@
 """Base class for agent tools."""
 
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
 from typing import Any
 

nanobot/agent/tools/cron.py

@@ -1,5 +1,7 @@
 """Cron tool for scheduling reminders and tasks."""
 
+from __future__ import annotations
+
 from contextvars import ContextVar
 from typing import Any
 

nanobot/agent/tools/filesystem.py

@@ -1,5 +1,7 @@
 """File system tools: read, write, edit."""
 
+from __future__ import annotations
+
 import difflib
 from pathlib import Path
 from typing import Any

nanobot/agent/tools/mcp.py

@@ -1,5 +1,7 @@
 """MCP client: connects to MCP servers and wraps their tools as native nanobot tools."""
 
+from __future__ import annotations
+
 import asyncio
 from contextlib import AsyncExitStack
 from typing import Any

nanobot/agent/tools/message.py

@@ -1,5 +1,7 @@
 """Message tool for sending messages to users."""
 
+from __future__ import annotations
+
 from typing import Any, Awaitable, Callable
 
 from nanobot.agent.tools.base import Tool

nanobot/agent/tools/registry.py

@@ -1,5 +1,7 @@
 """Tool registry for dynamic tool management."""
 
+from __future__ import annotations
+
 from typing import Any
 
 from nanobot.agent.tools.base import Tool

nanobot/agent/tools/shell.py

@@ -1,5 +1,7 @@
 """Shell execution tool."""
 
+from __future__ import annotations
+
 import asyncio
 import os
 import re

nanobot/agent/tools/spawn.py

@@ -1,5 +1,7 @@
 """Spawn tool for creating background subagents."""
 
+from __future__ import annotations
+
 from typing import TYPE_CHECKING, Any
 
 from nanobot.agent.tools.base import Tool

nanobot/agent/tools/web.py

@@ -1,5 +1,7 @@
 """Web tools: web_search and web_fetch."""
 
+from __future__ import annotations
+
 import html
 import json
 import os

nanobot/bus/events.py

@@ -1,5 +1,7 @@
 """Event types for the message bus."""
 
+from __future__ import annotations
+
 from dataclasses import dataclass, field
 from datetime import datetime
 from typing import Any

nanobot/channels/base.py

@@ -1,5 +1,7 @@
 """Base channel interface for chat platforms."""
 
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
 from typing import Any
 

nanobot/channels/dingtalk.py

@@ -1,5 +1,7 @@
 """DingTalk/DingDing channel implementation using Stream Mode."""
 
+from __future__ import annotations
+
 import asyncio
 import json
 import mimetypes

nanobot/channels/discord.py

@@ -1,5 +1,7 @@
 """Discord channel implementation using Discord Gateway websocket."""
 
+from __future__ import annotations
+
 import asyncio
 import json
 from pathlib import Path

nanobot/channels/email.py

@@ -1,5 +1,7 @@
 """Email channel implementation using IMAP polling + SMTP replies."""
 
+from __future__ import annotations
+
 import asyncio
 import html
 import imaplib

nanobot/channels/feishu.py

@@ -1,5 +1,7 @@
 """Feishu/Lark channel implementation using lark-oapi SDK with WebSocket long connection."""
 
+from __future__ import annotations
+
 import asyncio
 import json
 import os

nanobot/channels/matrix.py

@@ -1,5 +1,7 @@
 """Matrix (Element) channel — inbound sync + outbound message/media delivery."""
 
+from __future__ import annotations
+
 import asyncio
 import logging
 import mimetypes

nanobot/channels/qq.py

@@ -1,5 +1,7 @@
 """QQ channel implementation using botpy SDK."""
 
+from __future__ import annotations
+
 import asyncio
 from collections import deque
 from typing import TYPE_CHECKING

nanobot/channels/slack.py

@@ -1,5 +1,7 @@
 """Slack channel implementation using Socket Mode."""
 
+from __future__ import annotations
+
 import asyncio
 import re
 from typing import Any

nanobot/cli/commands.py

@@ -1,5 +1,7 @@
 """CLI commands for nanobot."""
 
+from __future__ import annotations
+
 import asyncio
 import os
 import select

nanobot/config/loader.py

@@ -1,5 +1,7 @@
 """Configuration loading utilities."""
 
+from __future__ import annotations
+
 import json
 from pathlib import Path
 

nanobot/config/schema.py

@@ -1,5 +1,7 @@
 """Configuration schema using Pydantic."""
 
+from __future__ import annotations
+
 from pathlib import Path
 from typing import Literal
 

nanobot/cron/service.py

@@ -1,5 +1,7 @@
 """Cron service for scheduling agent tasks."""
 
+from __future__ import annotations
+
 import asyncio
 import json
 import time

nanobot/cron/types.py

@@ -1,5 +1,7 @@
 """Cron types."""
 
+from __future__ import annotations
+
 from dataclasses import dataclass, field
 from typing import Literal
 

nanobot/providers/base.py

@@ -1,5 +1,7 @@
 """Base LLM provider interface."""
 
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field
 from typing import Any

nanobot/providers/litellm_provider.py

@@ -1,5 +1,7 @@
 """LiteLLM provider implementation for multi-provider support."""
 
+from __future__ import annotations
+
 import os
 import secrets
 import string

nanobot/providers/transcription.py

@@ -1,5 +1,7 @@
 """Voice transcription provider using Groq."""
 
+from __future__ import annotations
+
 import os
 from pathlib import Path
 

nanobot/session/manager.py

@@ -1,5 +1,7 @@
 """Session management for conversation history."""
 
+from __future__ import annotations
+
 import json
 import shutil
 from dataclasses import dataclass, field