Canada limitations (v1.1)

Honest scope for v1.1:

• No lat/lng resolution — no Canadian boundary source is onboarded; use a postal code (A1A 1A1).
• General sales tax rates only. No product-level taxability (zero-rated groceries, books exemptions, PST-exempt services), no place-of-supply rules for services/intangibles, no small-supplier thresholds. The rate returned is the general rate for tangible retail sales at the destination.
• Rooftop precision is not needed for the general rate — provinces are uniform — but municipal accommodation/lodging taxes (e.g. MAT) are out of scope.
• /v1/freshness does not report Canadian rows in v1.1; provincial rates change by budget act and each response carries its own effective_from + statute_ref.
• Beta billing: Canadian lookups are unbilled during the beta window; this will change with notice when the beta ends.