v26.7.2-rc.2

chdb-core v26.7.2-rc.2 (pre-release)

Full changelog: v26.7.1-rc.1...v26.7.2-rc.2 — 55 commits, 10 pull requests.
ClickHouse baseline unchanged: v26.7.2.1-stable.

🚀 New features

• Backup, restore and query classification in the C ABI (#202) — chdb_backup_database_n,
  chdb_restore_database_n and chdb_classify_query_n. A caller passes the database name and
  the archive path as separate arguments instead of assembling BACKUP DATABASE ... TO File(...)
  and quoting it itself, and can ask the parser what a statement does without executing it: its
  class, how many executable statements the text holds, whether it carries a credential, and
  whether every persistent write lands in one named database. The report is versioned by size,
  so a caller that sets struct_size gets a refusal rather than a write past the end of its
  struct. The same surface is exposed through _chdb.connect in the Python module.
• chdb_shutdown() (#185) — stops the engine's thread pools. The transition is atomic
  against concurrent connects and against itself.

🐛 Bug fixes

• ADBC entrypoints are exported from Linux Python wheels (#189), and Arrow ADBC compatibility
  options now propagate (#197).
• Connection argv settings apply to the connection's own session (#196).
• libchdb.a no longer exposes bundled libc++ / libc++abi / libunwind symbols, on macOS and on
  Linux (#199).
• chdb.h ships world-readable in the libchdb release tarballs (#195).

🔧 CI / build / release

• A release tag now has to name the ClickHouse line the tree is synced to, and the library
  reports the version it was actually built as rather than the newest tag lying around (#184).
• Pre-releases no longer ask the language bindings to adopt them (#184).
• Linux ARM64 debuginfo is packaged as tar.xz to stay under GitHub's 2 GiB asset limit (#201).
• CI workflows are hardened against self-hosted runner infrastructure failures (#208).

Notes on this pre-release

• Not published to PyPI. Install from the wheels attached below.
• The attached wheels are versioned 26.7.2 — the -rc.2 suffix is dropped by the version-bump
  step, so the filename does not distinguish this candidate from a future v26.7.2.
  chdb_version() and SELECT chdb() report 26.7.2-rc.2 correctly.