Categorize rejected xerial tests as permanent or addressable #172

Problem

upstream-xerial_sqlite-jdbc.manifest records every rejected test with a prose reason, but the reasons are not categorized, so it is not obvious which rejections are permanent and which could be reversed. Some rejections are also stale: SavepointTest is rejected as "not implemented", but SQLite SAVEPOINT SQL over Hrana makes it implementable; MathFunctionsTest depends only on the server build enabling SQLITE_ENABLE_MATH_FUNCTIONS.

Proposed change

Add a category tag to each rejected line (for example # permanent: native-api, # permanent: config-surface, # permanent: remote-model, # build-flag, # addressable: savepoints) and correct any rationale that later PRs changed.

Acceptance criteria

• Every rejected class carries a category.
• Addressable classes (savepoints, and math functions if the sqld build supports it) are called out distinctly from permanent exclusions.
• tools/export-upstream --verify still passes after the manifest edit.