fix(evidence): validate curated runtime corpus

harness/tht/cli/preprocess_cmd.py

@@ -75,6 +75,18 @@ def _candidate_evaluator(cfg, *, vector_store, embedder):
     return evaluate
 
 
+def _validate_materialized_curated_corpus(cfg) -> None:
+    """Fail closed on a v2 pinned filesystem corpus before any vector write is possible."""
+    if cfg.evidence is None or cfg.evidence.schema_version != 2:
+        return
+    if not any(source.type == "filesystem" for source in cfg.evidence.sources):
+        return
+    from tht.evidence import validate_workspace_evidence
+
+    if not validate_workspace_evidence(_evaluation_workspace_root(cfg)).publishable:
+        raise RuntimeError("curated Evidence corpus is invalid")
+
+
 def _evidence_json_payload(cfg, payload: dict, *, code: str, error: str | None = None) -> dict:
     value = {
         **payload,
@@ -158,6 +170,7 @@ def run_from_config(config: Path, *, dry_run: bool = False, resume: str | None =
     cfg = _load_config_or_exit(config)
     if cfg.embeddings is None:
         raise RuntimeError("embeddings are not configured")
+    _validate_materialized_curated_corpus(cfg)
     corpus_root = cfg.paths.artifacts.parent / "corpus"
     vector_store = build_vector_store(cfg, require_write=True)
     embedder = make_embedder(cfg.embeddings)