fix: remove duplicate import, tidy MatrixConfig comments

nanobot/config/schema.py

@@ -6,7 +6,6 @@ from typing import Literal
 from pydantic import BaseModel, Field, ConfigDict
 from pydantic.alias_generators import to_camel
 from pydantic_settings import BaseSettings
-from typing import Literal
 
 
 class Base(BaseModel):
@@ -187,18 +186,14 @@ class QQConfig(Base):
 
 class MatrixConfig(Base):
     """Matrix (Element) channel configuration."""
-
     enabled: bool = False
     homeserver: str = "https://matrix.org"
     access_token: str = ""
-    user_id: str = ""  # @bot:matrix.org
+    user_id: str = ""                       # e.g. @bot:matrix.org
     device_id: str = ""
-    # Enable Matrix E2EE support (encryption + encrypted room handling).
-    e2ee_enabled: bool = True
-    # Max seconds to wait for sync_forever to stop gracefully before cancellation fallback.
-    sync_stop_grace_seconds: int = 2
-    # Max attachment size accepted for Matrix media handling (inbound + outbound).
-    max_media_bytes: int = 20 * 1024 * 1024
+    e2ee_enabled: bool = True               # end-to-end encryption support
+    sync_stop_grace_seconds: int = 2        # graceful sync_forever shutdown timeout
+    max_media_bytes: int = 20 * 1024 * 1024 # inbound + outbound attachment limit
     allow_from: list[str] = Field(default_factory=list)
     group_policy: Literal["open", "mention", "allowlist"] = "open"
     group_allow_from: list[str] = Field(default_factory=list)