docs: add implementation plan for income budget report Group A (type 1-3)
Bite-sized task breakdown implementing the design in docs/superpowers/specs/2026-08-05-income-budget-report-native-design.md, scoped to Group A only (income-budget-report-income1, type_id 1) per the writing-plans skill's guidance to split independently-testable subsystems into separate plans. Group B (type 4-6) and Group C (type 10) are explicitly out of scope, tracked as follow-up plans. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_011R9j5gaw2qsoh9ypWQeXxi
This commit is contained in: