refactor: extract shared error hierarchy + Session into idatui/errors.py

The IDAError/IDAConnectionError/IDAToolError/... exceptions and the Session
dataclass were defined in client.py (the ida-pro-mcp HTTP client), but the idalib
worker path (worker_client/domain/app) needs them without the HTTP transport.
Move them to a transport-agnostic errors.py; client.py re-exports them so the
deprecated mcp tooling and stress tests are unchanged (verified:
errors.IDAToolError IS client.IDAToolError, so cross-module `except` still works).

worker_client, domain (TYPE_CHECKING-guarded IDAClient hint), app, and __init__
now import the shared types from errors.py. This decouples the worker path from
client.py at runtime -- the prerequisite for deleting the mcp transport.

1 files changed, 5 insertions, 2 deletions

diff --git a/idatui/domain.py b/idatui/domain.py
index 2a3fc2b..4f72f5b 100644
--- a/idatui/domain.py
+++ b/idatui/domain.py
@@ -28,9 +28,12 @@ import threading
 import urllib.request
 from concurrent.futures import ThreadPoolExecutor
 from dataclasses import dataclass, field, replace
-from typing import Callable
+from typing import Callable, TYPE_CHECKING
 
-from .client import IDAClient, IDAToolError
+from .errors import IDAToolError
+
+if TYPE_CHECKING:  # type hint only; the runtime client is mcp IDAClient or worker
+    from .client import IDAClient  # noqa: F401
 
 # Clamps derived from measured caps (list ~700, disasm ~500). Margin included.
 LIST_PAGE = 500