fix(config-ini): strip inline # and ; comments from values

The module docstring teaches inline comments — `mode = master    # or
"agent"` is the canonical example for the [decnet] section. Python's
configparser ignores those by default unless inline_comment_prefixes
is set explicitly, so the comment became part of the value and
downstream validators rejected it ("mode must be 'agent' or 'master',
got 'master                       # or \"agent\"'").

Hit live on first VPS deploy: every CLI invocation crashed at import
time with a stack trace that didn't make it obvious the docstring's
example was the trigger. Now the parser does what the docs promise.

decnet/config_ini.py

@@ -158,7 +158,14 @@ def load_ini_config(path: Optional[Path] = None) -> Optional[Path]:
     if not path.is_file():
         return None
 
-    parser = configparser.ConfigParser()
+    # The docstring at the top of this module advertises inline ``#`` and
+    # ``;`` comments (e.g. ``mode = master    # or "agent"``). Python's
+    # ``configparser`` only recognises those when ``inline_comment_prefixes``
+    # is set explicitly — without it, the comment becomes part of the value
+    # and downstream validators reject it ("mode must be 'agent' or 'master',
+    # got 'master                  # or \"agent\"'"). Match what the docs
+    # promise.
+    parser = configparser.ConfigParser(inline_comment_prefixes=("#", ";"))
     parser.read(path)
 
     # [decnet] first — mode/disallow-master/log-directory. These seed the