v0.3.0

Adds Max-only weekly Opus sub-cap support: when the API returns seven_day_opus, it now shows as an extra "Weekly Opus" row and participates in the "closest to limit" calculation.

Unverified against a real Max account — implemented defensively (nil-safe, no-op on Pro). If it looks wrong on Max, please open an issue with a redacted response body from the spike script in the README.

Also documents plan support (Pro/Max/Free/Team) in the README.