bloom

Imported from YimingQiao/bloom (AGENTS.md). Install upstream with npx skills add YimingQiao/bloom. Copyright stays with the author.

Bloomsea development rules

• Do not add try/catch blocks to extension-owned C++ under src/. Runtime, I/O, deserialization, and worker errors must propagate to the caller instead of being hidden or converted into a silent fallback.
• Use D_ASSERT for internal invariants. Invalid user input and failures that can occur in a valid release build still require an explicit DuckDB exception.
• Use DuckDB's Executor and TaskExecutor directly. On the normal path, explicitly call CancelTasks() or WorkOnTasks() before either the executor or state borrowed by its tasks is destroyed; do not add scoped executor wrappers solely for exceptional-path cleanup.
• Keep every project header under src/include/.
• Do not introduce a new class, result wrapper, enum, or source file unless it owns a distinct responsibility that cannot remain a local implementation detail.
• Treat a very large source file as a signal to review its responsibilities. First split the owning class by state lifecycle and invariant; moving one unchanged class across several .cpp files is not an architectural split. Keep a thin coordinator only when the extracted components own real state, and group multiple implementation files in a same-named module directory.
• Treat instant sampling as one module. Keep shared scheduling/selection logic in instant_sampler/common.* and backend-specific code in native.cpp or parquet.cpp; avoid duplicating backend branches in the estimator.
• Keep prepared-sample acquisition, persistence, and preload behavior in prepared_sampler.*; the sampling estimator only selects a mode and evaluates predicates against the resulting sample.