Harden SQLite execution and lifecycle handling

[martian56]

What changed

• add checked binding, stepping, reading, reset, finalize, timeout, and close APIs
• preserve SQLite execution errors, embedded NUL text, and result column metadata
• expand lifecycle, transaction, boundary, and large-value coverage
• test Raven 2.26.1 on Linux and Windows
• prepare version 0.2.0 with a changelog

Why

The original convenience APIs discarded several SQLite return codes, so constraint, binding, and close failures could be mistaken for normal completion. The checked APIs preserve compatibility while allowing callers to handle every database failure.

Validation

• rvpm fmt --check
• rvpm build
• rvpm test (15 passed)
• rvpm doc