validateAgentSection function

void validateAgentSection(Object? node)

The strict agent: section validator, shared by check, set and the settings flow (issues #394/#680). Mirrors the private boot parser in cli_config.dart (pinned by test): the section takes exactly contextWindowCap (a positive integer at or above the compaction reserve — a cap below 16384 must never soften that floor; a cap above the catalog window is the #729 raise path and validates unchanged), mode (the load preset default|pi|omp, validated by the shared agentLoadModeValidationError rule), misuseBreaker (a boolean — gh-1572 makes the emitter render the kill switch, so the mirror has to accept it or fa config check false-fails on fa's own output) and stuckTool (validated with the section's own strict parser, the same one the boot parser applies).

The per-key checks live in _agentKeyValidators — the same table-driven shape the section dispatch above uses — so the dispatch function itself stays flat (the gh-1572 rework's two new keys pushed the switch form over the repo's CRAP ratchet; the table cannot drift the same way a switch can).

Implementation

void validateAgentSection(Object? node) {
  if (node is! YamlMap) {
    throw ConfigException('must be a map, got: $node');
  }
  for (final entry in node.entries) {
    final validate = _agentKeyValidators['${entry.key}'];
    if (validate == null) {
      throw ConfigException('unknown "agent" key: ${entry.key}');
    }
    validate(entry.value);
  }
}