feat: harden runtime readiness and session workflow

harness/tht/cli/preprocess_cmd.py

@@ -10,6 +10,7 @@ from pathlib import Path
 import typer
 
 from tht.cli.config_cmd import CONFIG_OPT
+from tht.config import workspace_id_from_path
 
 
 preprocess_app = typer.Typer(help="Materialize versioned preprocessing artifacts")
@@ -86,7 +87,7 @@ def run_from_config(config: Path, *, dry_run: bool = False, resume: str | None =
         return "sha256:" + hashlib.sha256(value.encode()).hexdigest()
 
     return pipeline.run_as_job(
-        workspace_id=config.stem.lower().replace(".", "-").replace("_", "-"),
+        workspace_id=workspace_id_from_path(config),
         workspace_root=corpus_root.parent,
         config_fingerprint=fingerprint(cfg.model_dump_json()),
         input_fingerprint=fingerprint(config.resolve().as_posix()),
@@ -115,7 +116,7 @@ def gc_from_config(config: Path, *, dry_run: bool = False):
         pipeline_version="evidence-v1",
         retain_published_generations=cfg.vector.retain_published_generations,
     )
-    pipeline.workspace_id = config.stem.lower().replace(".", "-").replace("_", "-")
+    pipeline.workspace_id = workspace_id_from_path(config)
     return pipeline.gc(workspace_root=corpus_root.parent, dry_run=dry_run)