Point v0.1.24

Added

• Phase 32: opaque Duration type (integer seconds at runtime) with JS/TS/Python emit parity.
• Phase 32: std.time duration helpers — duration from seconds, duration to seconds, duration minutes.
• Phase 32: examples/tools/duration-demo.point; Duration → BIGINT/INTEGER in build-schema.
• Phase 32: language-primitive-audit.md synced — Map shipped, Money/errors patterns documented.