Request: PRAGMA data_version support

Use case

Building change-detection and pub/sub primitives on libsql (similar to Honker, pg_notify style queues, durable streams).

PRAGMA data_version is the critical dependency — it provides a version counter that increments on every commit, enabling:

• Cross-process change detection via polling (1ms intervals)
• Push-like async semantics without a broker
• Detecting when another connection modified the DB

Currently libsql doesn't support PRAGMA data_version (shown in compatibility matrix as ❌).

Questions

1. Why was data_version omitted? Architectural constraint, low priority, or something else?
2. Would you accept a PR to implement it?
3. Does it conflict with libsql's replication/distributed model?

For local-mode libsql (single DB file), data_version should be straightforward — it's a pager-level counter in SQLite. For libsql-server, it's trickier (need server-side tracking), but worth discussing.

Context

• data_version exists in SQLite since 3.3.7
• Used by better-sqlite3, Honker, and other change-tracking systems
• WAL mode + data_version enables efficient cross-process notifications

Would love to know the reasoning. If there's a fundamental reason it can't/shouldn't be implemented, I can explore alternatives.

Start with the compatibility matrix in COMPAT.md and the repository's pager-level handling of PRAGMA behavior. Determine whether the requested semantics apply to local mode, libsql-server, or both, then clarify the expected counter behavior and test coverage before implementation. Done means an agreed scope and a compatible data_version implementation.