check can return clean while a newly created source file references missing symbols

[XertroV]

While developing an Openplanet plugin with openplanet-lsp check --define UNIT_TEST ., newly created src/*_Test.as files intermittently were not incorporated immediately. The command exited 0 with no diagnostics even though the new file referenced helpers that did not exist yet; editor diagnostics sometimes disagreed. Existing source edits were diagnosed correctly.

Repro observed on Openplanet type DB 1.29.14 / openplanet-lsp check on 2026-09-11:

1. Start from a clean plugin root.
2. Create a new src/Foo_Test.as containing a call to missing Foo::Bar().
3. Immediately run openplanet-lsp check --define UNIT_TEST . (also reproduced with --no-gitignore).
4. The command can report 0 errors/warnings rather than the expected undefined symbol. A later refresh/edit may discover it.

Expected: each one-shot check performs deterministic source discovery and reports missing identifiers in newly created .as files.