fix(core): preserve adapter command contracts

harness/tht/cli/schema_cmd.py

@@ -1,4 +1,5 @@
 from pathlib import Path
+import logging
 
 import typer
 from tht.adapters.factory import build_dwh
@@ -8,6 +9,23 @@ from tht.db.sampling import is_text_type
 from tht.mschema.eligibility import classify_all
 
 schema_app = typer.Typer(help="Gestione mschema (rappresentazione canonica dello schema)")
+logger = logging.getLogger(__name__)
+
+
+def _add_examples(dwh, phys, examples) -> None:
+    for table_name, table in phys.tables.items():
+        for column_name, column in table.columns.items():
+            if not is_text_type(column.type):
+                continue
+            try:
+                sampled = dwh.sample_column(
+                    table_name, column_name, limit=examples.max_per_column
+                )
+            except Exception as exc:
+                logger.warning("Campionamento saltato per %s.%s: %s",
+                               table_name, column_name, exc)
+                continue
+            column.examples = [str(value) for value in sampled if value not in (None, "")]
 
 
 def _load_config_or_exit(config: Path):
@@ -64,18 +82,7 @@ def introspect_cmd(
     try:
         dwh = build_dwh(cfg)
         phys = dwh.introspect()
-        for table_name, table in phys.tables.items():
-            for column_name, column in table.columns.items():
-                if is_text_type(column.type):
-                    column.examples = [
-                        str(value)
-                        for value in dwh.sample_column(
-                            table_name,
-                            column_name,
-                            limit=cfg.examples.max_per_column,
-                        )
-                        if value not in (None, "")
-                    ]
+        _add_examples(dwh, phys, cfg.examples)
         classify_all(phys, cfg.eligibility)
     except Exception as e:
         typer.secho(f"ERRORE: {e}", fg=typer.colors.RED, err=True)