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

tests/config/test_config_ini.py

@@ -27,6 +27,24 @@ def test_missing_file_is_noop(monkeypatch, tmp_path):
     assert "DECNET_AGENT_PORT" not in os.environ
 
 
+def test_inline_comments_stripped_from_values(monkeypatch, tmp_path):
+    """The module docstring teaches inline ``#`` comments — the parser
+    must accept them. Hit live on the first VPS deploy 2026-04-28: a
+    ``mode = master    # or "agent"`` line caused the value to be parsed
+    as ``master                  # or "agent"`` and downstream
+    validators rejected it."""
+    _scrub(monkeypatch, "DECNET_MODE", "DECNET_API_PORT")
+    ini = _write_ini(tmp_path, """
+[decnet]
+mode = master   # inline hash comment
+[master]
+api-port = 8000   ; inline semi comment
+""")
+    load_ini_config(ini)
+    assert os.environ["DECNET_MODE"] == "master"
+    assert os.environ["DECNET_API_PORT"] == "8000"
+
+
 def test_agent_section_only_loaded_when_mode_agent(monkeypatch, tmp_path):
     _scrub(
         monkeypatch,