fix(pg): close pg regress compatibility gaps

[rebelice]

Summary

• Add PostgreSQL compatibility for ALTER ADD IDENTITY, OUT-only function return inference, partition child primary keys, and ALTER DOMAIN ADD NOT NULL parsing.
• Expand parser surface for LIKE/ILIKE ANY/ALL, parenthesized INSERT SELECT, SQL/JSON/view SELECT shapes, foreign column OPTIONS, and interval column references.
• Harden pgregress statement extraction/sanitization and update known failures to 161 with no new failures.

Test Plan

• go test ./pg/parser -run TestParseAlterDomainAddNotNullConstraint -count=1 -v
• go test ./pg/pgregress -run TestPGRegress -count=1 -update -v
• git diff --check
• go test ./pg/... -count=1