Update Colorado AND-CS 2026 grant standard

[MaxGhenis]

Summary

• add the 2026 Colorado AND-CS grant standard of $994 from current 9 CCR 2503-5 section 3.546
• add a baseline regression case for the 2026 state supplement calculation

Tests

• uv run policyengine-core test policyengine_us/tests/policy/baseline/gov/states/co/ssa/state_supplement -c policyengine_us -v

[MaxGhenis]

Superseded by #8807, which merged the identical AND-CS 2026 grant standard ($994 effective 2026-01-01, 9 CCR 2503-5 §3.546(A)) at the same file position; this branch now conflicts on the duplicate hunks. The $994 figure was independently re-verified against the CCR PDF text (printed page 98). Closing.