fix(runtime): do not treat trivial attachment reads as substantive scientific execution

[HaoxuanLiTHUAI]

Summary

A trivial attachment read can be classified as substantive scientific execution, triggering the Principal workflow guard, unnecessary trace work, and repeated final replies.

Reproduction

Upload a small text file named brainpilot-safari-upload-test.txt and ask:

Read the attached synthetic test file and reply with exactly the value after session-isolation-marker, with no other text.

Observed

• The Principal correctly reads the 135-byte file.
• It emits the requested marker three times as three distinct persisted assistant messages.
• A warning is persisted: Principal ignored the required Expert-delegation reminder; the research workflow remains incomplete.
• The trivial task consumes about 69,970 tokens including trace processing.

This is not history/SSE replay duplication: the three messages have different message_id values.

Root cause

isSubstantiveScientificExecutionRequest() treats attached ... file as concrete input and matches the adjective test in “test file” as an input-bound execution action.

Acceptance criteria

• Attachment notices and filenames do not influence execution-intent classification.
• “Read/quote/extract this test file” stays non-substantive.
• “Test/evaluate/analyze the attached dataset” remains substantive.
• The reproduction produces one final answer and no delegation violation.