Playground latest runtime fails before WordPress boot with SQLite ABSPATH fatal

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Summary

Running a WP Codebox recipe with the default latest WordPress runtime can fail before WordPress boots. The failure happens inside Playground's SQLite preload path, before caller code or recipe workflow steps execute.

Observed failure

A Studio Web website-generation bench run using WP Codebox recipe-run failed during workflow.steps[0] startup with:

Recipe workflow steps[0] failed: WordPress Playground CLI exited while booting the runtime with exit code 1.
Fatal error: Uncaught Error: Undefined constant "ABSPATH" in /internal/shared/sqlite-database-integration/constants.php:39
Stack trace:
#0 /internal/shared/sqlite-database-integration/wp-includes/sqlite/db.php(15): require_once()
#1 /internal/shared/mu-plugins/sqlite-database-integration.php(42): require_once('/internal/share...')
#2 /internal/shared/preload/0-sqlite.php(57): require_once('/internal/share...')
#3 /internal/shared/preload/0-sqlite.php(33): Playground_SQLite_Integration_Loader->load_sqlite_integration()
#4 /internal/eval.php(10): Playground_SQLite_Integration_Loader->__call('check_connectio...', Array)

Expected behavior

latest should be a valid default WordPress runtime for WP Codebox recipes, including recipes that need the current WordPress AI/client runtime surface.

Notes

• This is separate from PR Centralize default WordPress runtime #715, which centralizes WP Codebox's default WordPress runtime as latest.
• Do not work around this by downgrading the default runtime. Downstream callers can explicitly pin a version when they intentionally need an older runtime, but the default should remain current.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (GPT-5.5)
• Used for: Capturing the observed failure and drafting the issue from lab run output.