v2.0.0 — per-round artifact filenames

Fix

The Evaluator could return a round-N verdict byte-identical to round 0 because eval-result.json and gen-result.md were shared filenames overwritten each round. Any failure to rewrite (skipped Write, crash between signal and write, defensive preservation of an existing file) left the prior round's bytes in place and the Planner read them unchanged. feedback-<R>.json was a derivative copy that masked the same defect.

Change

Per-round numbered artifacts under .adveloop/tasks/<N>/:

• gen-task-<R>.md
• gen-result-<R>.md
• eval-task-<R>.md
• eval-result-<R>.json

feedback-<R>.json removed — the previous round's eval-result-<R-1>.json is the next Generator's prior-feedback input directly.

Breaking

In-flight .adveloop/ directories from pre-2.0 runs cannot be resumed. The resume scan classifies them as pending and defaults the user's offer to Rewrite from scratch.