Bump vendored SQLite 3.42.0 → 3.53.2

[sinkingsugar]

Bumps the vendored SQLite amalgamation from 3.42.0 (2023-05-16) to 3.53.2 (2026-06-03) — ~4 years / 11 minor versions of upstream fixes and query-planner improvements.

What changed

• Replaced sqlite3.c, sqlite3.h, sqlite3ext.h, shell.c with the upstream 3.53.2 amalgamation.
• Re-applied the three local amalgamation patches (verified present via exact-once assertions):
  • guard <sys/statfs.h> out on macOS
  • enable the flock VFS via SQLITE_ENABLE_FLOCK (4 sites)
  • dlopen with RTLD_LOCAL | RTLD_DEEPBIND

Local validation

• ✅ Clean CMake build (no warnings)
• ✅ C unit tests (ctest) pass
• ✅ Python correctness suite: 155/155 pass
• ✅ CLI reports sqlite_version() = 3.53.2, extension loads
• ⏭️ ASan/valgrind deferred to CI — local ASan is unavailable on this Apple-Silicon Mac due to a re-entrant deadlock in the libclang_rt ASan runtime init (spins before main; unrelated to this change). The c-asan and c-valgrind jobs run on ubuntu-latest and cover it.

Notes

• No build-flag changes; the flock patch is a no-op unless SQLITE_ENABLE_FLOCK is defined (downstream Shards/iOS builds).
• For edge-talk to actually run on 3.53.2, Shards needs to pull in this updated cr-sqlite (separate downstream step).