feat: complete evidence restructuring worktree

harness/tht/cli/evidence_cmd.py

@@ -14,6 +14,7 @@ from tht.cli.config_cmd import CONFIG_OPT
 from tht.evidence import (
     EvidencePreparationError,
     PiEvidenceRestructurer,
+    migrate_workspace_evidence,
     prepare_workspace_evidence,
     resolve_workspace_evidence,
     validate_workspace_evidence,
@@ -174,6 +175,38 @@ def validate_cmd(
     raise typer.Exit(code=1)
 
 
+@evidence_app.command("migrate")
+def migrate_cmd(
+    workspace_root: Path,
+    json_output: Annotated[bool, typer.Option("--json", help="Write machine JSON to stdout.")] = False,
+) -> None:
+    """Rewrite legacy Curated units as readable Markdown without model calls."""
+    root = _canonical_worktree(workspace_root)
+    try:
+        report = migrate_workspace_evidence(root)
+    except EvidencePreparationError as error:
+        _emit({
+            "schemaVersion": 1,
+            "operation": "evidence_migrate",
+            "status": "failed",
+            "code": error.code,
+        }, json_output)
+        raise typer.Exit(code=1) from error
+    _emit({
+        "schemaVersion": 1,
+        "operation": "evidence_migrate",
+        "status": "migrated",
+        "migrated": list(report.migrated),
+        "unchanged": list(report.unchanged),
+        "findings": _findings_payload(report.findings),
+    }, json_output)
+    if report.findings:
+        if all(finding.code in {"orphaned_unit", "unresolved_review_item"}
+               for finding in report.findings):
+            raise typer.Exit(code=3)
+        raise typer.Exit(code=1)
+
+
 @evidence_app.command("evaluate")
 def evaluate_cmd(
     workspace_root: Path,