fix: clear all mypy errors

Annotate untyped containers and Optional attributes, type the stdlib-shaped
metric dicts in the client plugins, and add types-PyYAML/types-psutil to the
dev extras plus a mypy override for nio/mattermostdriver (no stubs).

Behaviour fixes found on the way: enable_kernel_timestamps() now returns False
when SO_TIMESTAMP is unknown instead of raising TypeError, send_shutdown is
defined at module level so cleanup() cannot hit a NameError, and a failed
subprocess returncode falls back to UNKNOWN.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

hbd/server/dns.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 from subprocess import Popen, PIPE, STDOUT
-from typing import Optional
+from typing import Any, Callable, Optional
 import asyncio
 import logging
 
@@ -79,8 +79,8 @@ async def dns_update_worker(
     hbdclass,
     cfg: dict,
     async_queue=None,
-    log: Optional[callable] = None,
-    pushmsg: Optional[callable] = None,
+    log: Optional[Callable[..., Any]] = None,
+    pushmsg: Optional[Callable[..., Any]] = None,
     loop: Optional[asyncio.AbstractEventLoop] = None,
 ):
     """Pure async DNS worker that processes updates from asyncio.Queue.
@@ -164,7 +164,7 @@ async def dns_update_worker(
 def start_dns_worker(
     hbdclass,
     cfg: dict,
-    log: Optional[callable] = None,
+    log: Optional[Callable[..., Any]] = None,
     loop: Optional[asyncio.AbstractEventLoop] = None,
 ):
     """Start the async DNS worker and return the Task.
@@ -176,7 +176,7 @@ def start_dns_worker(
         loop = asyncio.get_event_loop()
 
     # Create asyncio.Queue and wrap in a bridge for thread-safe puts
-    async_q = asyncio.Queue()
+    async_q: asyncio.Queue[Any] = asyncio.Queue()
 
     class _QueueBridge:
         """Thread-safe wrapper around asyncio.Queue for synchronous callers."""