feat: experiment log stream, to file and UI

Adds a few new logging utility classes. One to save to files with a date, one to support optional fields in formats, last to filter partial log messages.

ref: N25B-401

src/control_backend/logging/dated_file_handler.py

@@ -0,0 +1,29 @@
+from datetime import datetime
+from logging import FileHandler
+from pathlib import Path
+
+
+class DatedFileHandler(FileHandler):
+    def __init__(self, file_prefix: str, **kwargs):
+        if not file_prefix:
+            raise ValueError("`file_prefix` argument cannot be empty.")
+        self._file_prefix = file_prefix
+        kwargs["filename"] = self._make_filename()
+        super().__init__(**kwargs)
+
+    def _make_filename(self) -> str:
+        filepath = Path(f"{self._file_prefix}-{datetime.now():%Y%m%d-%H%M%S}.log")
+        if not filepath.parent.is_dir():
+            filepath.parent.mkdir(parents=True, exist_ok=True)
+        return str(filepath)
+
+    def do_rollover(self):
+        self.acquire()
+        try:
+            if self.stream:
+                self.stream.close()
+
+            self.baseFilename = self._make_filename()
+            self.stream = self._open()
+        finally:
+            self.release()