[kvlonge]

Why

SQL predicate expressions such as column IS NOT NULL could remain untyped even though their output type is deterministically Boolean. IS NULL predicates were also not recognized as non-null values.

Changes

• infer Boolean output types for comparison and predicate expression kinds
• infer IS NULL and IS NOT NULL outputs as non-null
• add focused output inference coverage

Verification

• focused SQL analysis tests: 72 passed
• Ruff and Ty checks passed for touched files
• Fensu passed
• uv sync --all-extras
• make check-ci
• public-repository hygiene scan
• cache-free static compile of the downstream 974-model project with the affected analysis boundary enabled: 0 errors, 0 warnings