fix: preserve Task 2 command loading contracts

harness/tht/cli/preprocess_cmd.py

@@ -1,5 +1,4 @@
 """One-shot preprocessing commands."""
-# ruff: noqa: BLE001
 
 from __future__ import annotations
 
@@ -99,7 +98,6 @@ def run_from_config(config: Path, *, dry_run: bool = False, resume: str | None =
 
 def gc_from_config(config: Path, *, dry_run: bool = False):
     from tht.adapters.factory import build_evidence_sources, build_vector_store
-    from tht.cli.schema_cmd import _load_config_or_exit
     from tht.cli.vector_cmd import make_embedder
     from tht.corpus.chunk import ChunkPolicy
     from tht.corpus.pipeline import CorpusPipeline
@@ -134,7 +132,7 @@ def evidence_cmd(
     if action == "gc":
         try:
             payload = gc_from_config(config, dry_run=dry_run)
-        except Exception:
+        except (OSError, RuntimeError, ValueError, TypeError, KeyError):
             payload = {"status": "failed", "error": "evidence cleanup failed"}
             if json_output:
                 typer.echo(json.dumps(payload, sort_keys=True))
@@ -155,7 +153,7 @@ def evidence_cmd(
         raise typer.Exit(code=2)
     try:
         result = run_from_config(config, dry_run=dry_run, resume=resume)
-    except Exception:
+    except (OSError, RuntimeError, ValueError, TypeError, KeyError):
         payload = {"status": "failed", "error": "preprocessing failed"}
         if json_output:
             typer.echo(json.dumps(payload, sort_keys=True))
@@ -206,7 +204,7 @@ def dwh_cmd(
         raise typer.Exit(code=2)
     try:
         result = run_dwh_from_config(config, steps=selected, resume=resume)
-    except Exception:
+    except (OSError, RuntimeError, ValueError, TypeError, KeyError):
         payload = {"status": "failed", "error": "DWH preprocessing failed"}
         if json_output:
             typer.echo(json.dumps(payload, sort_keys=True))