Keep loss-free trial output out of the tracked tree

[deepfates]

Summary

• write each live loss-free trial artifact inside the isolated temporary trial directory
• parse the serialized artifact back in the test so the inspectable record remains covered
• retain the checked-in JSON as a historical witness instead of rewriting it on every test run
• update the roadmap to reflect that 0.3.0 is public and 0.4.0 is prepared but unpublished

Why

The trial includes a current timestamp and fresh relay generation IDs. Running the ordinary test suite therefore changed a tracked file even when behavior was identical. Verification should be idempotent and leave a clean checkout.

Verification

• pnpm verify — 21 test files, 125 tests, build/typecheck/path guard and README examples passed
• repeated the focused loss-free integration test
• confirmed docs/trials/loss-free-trial.json has no diff after both runs
• git diff --check