feat(canopy-reporting): wire ACF-196 expenditures from state accounting

Context

generate_acf196 in services/canopy-reporting/src/reporting/tanf.rs:327-409 ships hardcoded 0,0,0 for federal/state/total expenditure amounts across all 12 ACF-196 categories. The function returns success but the financial fields are placeholders. Comment line 406 admits "ACF-196 stub generated (expenditures zero — requires state accounting)".

ACF-196 is a federal expenditure report and the zeros are a Pub 1075 / federal-grantee compliance issue once we're past UAT.

Acceptance criteria

• State accounting integration shape decided (FMIS direct? CSV import? state-specific)
• Federal expenditure column populated for each of the 12 ACF-196 categories
• State expenditure column populated
• Total expenditure column populated
• Integration test covering at least one non-zero category
• CHANGELOG entry under Changed

Surfaced by

Multi-agent plan-vs-code audit, 2026-05-05. Was untracked despite being a known production-readiness gap.