config parity (M2)

python (tai.py)	C++ (src/config/)	notes
Consts	consts.h Consts	same values
TOTAL_STEP_CAP/SYSINFO_TIMEOUT/LOOP_*/TIMEOUTs	Consts::*	—
DEFAULT_MODEL/DEFAULT_VOICE/OPENROUTER_MODEL	kDefaultModel/...	—
ZEN_FREE_MODELS/POLLINATIONS_MODELS/DEVPLACE_FREE_ROUTES	ZenFreeModels()/...	—
Config.init env mapping	Config::FromEnv	subset: home/model/keys/models/voice
SETTINGS_CATALOG keys	SettingsCatalog()	11 keys ported (subset)
Config.Get/settings_row	Config::Get	scalar lookup only
split_models	SplitModels	comma/semicolon split
known_model_ids	KnownModelIds	config lists + extra (no health/backend)
resolve_tag	ResolveTag	bots map + models + dir; no store/agent