PHP: fix memory leaks and resource management issues

[prateek-kumar-improving]

Summary

Fixes multiple memory leaks, a potential crash in debug builds, and a resource management gap.

Issue link

This Pull Request is linked to issue (URL): #175

Features / Behaviour Changes

• ValkeyGlide::close() and ValkeyGlideCluster::close() now actually release the underlying Rust client connection instead of being no-ops. Previously, connections were only released
  on garbage collection.

Implementation

#	Fix	File(s)
1	Check EG(exception) after _initialize_open_telemetry() — was returning SUCCESS with a pending exception, leaking config and causing undefined behavior in FFI	valkey_glide.c
2	Replace bare return NULL with goto cleanup_route in execute_command_with_route() validation checks — route_bytes and route.key were leaked	command_response.c
3	Guard efree(offset_str) / efree(count_str) with NULL checks in sort commands — crashes in PHP debug builds when no LIMIT option	valkey_glide_str_commands.c
4	Free buffered_commands in free_valkey_glide_object() — batch state leaked if object destroyed mid-batch	valkey_glide.c
5	Implement close() to call close_glide_client() — was a no-op, connections only released on GC	valkey_glide.c, valkey_glide_cluster.c

Testing

All integration tests will run.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one issue.
• Commit message has a detailed description of what changed and why.
• Tests are added or updated.
• CHANGELOG.md and documentation files are updated.
• Destination branch is correct - main or release
• Create merge commit if merging release branch into main, squash otherwise.

[jeremyprime]

Should the buffered commands also be cleaned up when close is called? This could be moved to a helper function and called here and in close.

This also applies to valkey_glide_cluster.c file.