server: mirror console output to a text log under logs/

The codebase logs everything via plain print() scattered across
tasks/ws/components - rather than touch every call site, stdout/stderr
are now duplicated (Tee) into logs/brewpi.<timestamp>.log alongside
the existing tracer .mat files, line-buffered so a crash doesn't lose
the tail of the log.

server/brewpi.py

@@ -1,6 +1,9 @@
 #!/usr/bin/env python3
 import asyncio
 import json
+import os
+import sys
+import time
 from utils import ChangedFloat
 from ws.message import MessageDispatcher
 from ws.server.ws_server_multi_user import WsServerMultiUser
@@ -23,7 +26,33 @@ DEFAULT_PLANT_PARAMS = {
 	"Td": 30
 }
 
+
+class Tee:
+	"""Duplicates writes to multiple streams - used to mirror stdout/stderr
+	(everything the rest of the codebase already reaches via print()) into
+	a log file under logs/ as well as the console, without having to touch
+	every print() call site."""
+
+	def __init__(self, *streams):
+		self.streams = streams
+
+	def write(self, data):
+		for stream in self.streams:
+			stream.write(data)
+
+	def flush(self):
+		for stream in self.streams:
+			stream.flush()
+
+
 if __name__ == '__main__':
+	os.makedirs("logs", exist_ok=True)
+	log_path = "logs/brewpi.{}.log".format(time.strftime("%Y%m%d%H%M%S", time.localtime()))
+	log_file = open(log_path, "a", buffering=1)
+	sys.stdout = Tee(sys.stdout, log_file)
+	sys.stderr = Tee(sys.stderr, log_file)
+	print("Logging to {}".format(log_path))
+
 	parser = ap.ArgumentParser()
 	parser.add_argument("-d", "--debug", action="store_true")
 	parser.add_argument("-c", "--config", default="config.json")