Implement dynamic CrateDB server version detection in PDOConnection

[coderabbitai]

Context

Currently, PDOConnection::getServerVersion() returns a hardcoded version string "5.0.0" (see src/Crate/DBAL/Driver/PDOCrate/PDOConnection.php).

This hardcoded approach was discussed in PR #122 (comment thread: #122 (comment)).

Problem

The hardcoded version assumes all CrateDB deployments are running a modern version (>= 4.0.0), which causes Driver::createDatabasePlatformForVersion() to always select CratePlatform4(). This may cause issues if the actual server is running an older CrateDB version that requires a different platform implementation.

Proposed Solution

Implement dynamic version detection by querying the CrateDB server. CrateDB supports:

• SELECT version(); - returns CrateDB version string
• SELECT version FROM sys.nodes; - returns version per node

The version can be retrieved via the existing query() or exec() methods in PDOConnection.

Discussion Summary

From PR #122 discussion:

• @amotl initially changed the hardcoded version from "6.0.0" to "5.0.0" as a more conservative choice
• @seut expressed concern about hardcoding this value and requested proper version detection, at least as a followup
• The pragmatic approach for now is to assume modern CrateDB versions by default

References

• PR: Support for Doctrine DBAL 3 #122
• Comment thread: Support for Doctrine DBAL 3 #122 (comment)
• Requested by: @amotl
• Reviewed by: @seut

Acceptance Criteria

• getServerVersion() queries the actual CrateDB server for its version
• Proper error handling if version detection fails
• Consider caching the version to avoid repeated queries
• Update documentation to reflect minimum supported CrateDB version

[amotl]

It looks like DBAL can't automatically select the right platform implementation based on the remote database server version. Please correct me if you think I'm wrong, it can certainly be an oversight. 🙏

• DBAL3: Properly implement getDatabasePlatform? #159