In KDL, a `{ }` block's children are newline- or semicolon-separated,
so a block like `restart { policy "always" backoff-initial "10ms" }`
written on one line parses as a SINGLE node named `policy` whose
remaining words become extra arguments, not sibling keys. The parser
only ever read the first argument of each child node, so every key
after the first was silently discarded with no error.
Add `single_arg`, applied to every restart/stop/wait-for key that
takes exactly one value (all except `wait-for`'s `args`, which
legitimately takes zero or more), so a one-line block with 2+ keys
now fails to parse instead of silently keeping defaults.
`optional_string_map` (the `env { }` block) has the identical trap
but is out of scope here: it returns a bare BTreeMap with no error
path and would need a signature change to report a config error.
A second `command` node silently overwrote the first via a scalar
Option<PathBuf>, and a second `args` node silently overwrote the first
via a plain Vec, so duplicate keys last-won instead of tripping the
exactly-one-condition rule. Track args as Option<Vec<String>> and
error immediately on a repeated command or args key.
Adds kdl_parse module with parse_server_config() that deserialises a
KDL document into ServerConfig, with full validation of name, types,
durations, and restart/stop blocks. Also derives Default on
RestartPolicy to satisfy clippy.
logaritmisk