Returns the state-level rule plus any council-level rules on record. In
Queensland the state sets no standard at all, so the council rules are the
only real figures - the state row exists to say so.

Args:
    state: State or territory code, e.g. NSW, VIC, QLD, WA, SA, TAS, ACT, NT.
    lga: Optional council name filter, e.g. "Moreton Bay". Partial matches work.

Planning law changes often - Victoria alone saw five amendments touching
secondary dwellings between 2023 and 2025. Call this before relying on a
rule for a decision, and warn the user about anything flagged stale.

Args:
    max_age_months: Rules older than this many months are reported as stale.