chore: clear deferred review nits (error repr + two docstrings)

CHANGELOG.md

@@ -5,6 +5,15 @@ follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
+### Changed
+
+- The "mode_type not allowed for kind" contract error now quotes the offending
+  `mode_type` and `kind` (`repr`), matching the sibling "must be one of" error,
+  so an empty or whitespace value is legible. Docstring fixes only alongside:
+  the postgres `ensure_table` port-signature reference (0.6.0 → 0.8.0) and the
+  `ensure_unique_key` message-order claim (pyarrow grouping order is not
+  contractual).
+
 ## [0.9.0] - 2026-10-11
 
 ### Added

adapters/postgres/continuo_postgres_adapter/adapter.py

@@ -706,7 +706,7 @@ def ensure_table(
         this engine's physical-layout vocabulary — ``indexes`` — validated by
         :func:`_validated_indexes` before any DDL runs, so a malformed config
         never leaves a half-built table behind (fail closed). Required and
-        keyword-only, matching the contract 0.6.0 port signature. The create
+        keyword-only, matching the contract 0.8.0 port signature. The create
         and every index either all land or none do, in the same explicit
         BEGIN/COMMIT/ROLLBACK shape build_empty_from_columns uses.
 

continuo_python_runtime/contract/loader.py

@@ -302,7 +302,7 @@ def parse_node(
         )
     if mode_type not in rules.mode_types:
         raise ContractError(
-            f"{label}: 'mode_type' {mode_type} is not allowed for kind {kind} "
+            f"{label}: 'mode_type' {mode_type!r} is not allowed for kind {kind!r} "
             f"(allowed: {sorted(rules.mode_types)})"
         )
 

contract/continuo_engine_contract/keys.py

@@ -29,9 +29,9 @@ def ensure_unique_key(data: "pyarrow.Table", primary_key: Sequence[str]) -> None
     Groups the rows by the key columns. NULL counts as a value here; the
     contract requires every key column to be ``nullable: false`` and the
     harness's ``conform()`` rejects NULLs in such columns before this runs.
-    The message names the first repeated keys, in order of first appearance,
-    with their row counts. Only methods of *data* are called, so this module
-    needs no pyarrow import.
+    The message names up to a fixed number of the repeated keys with their row
+    counts; their order follows pyarrow's grouping and is not contractual. Only
+    methods of *data* are called, so this module needs no pyarrow import.
 
     Raises:
         ValueError: If *primary_key* is empty, names a column *data* lacks, or

tests/contract/test_loader.py

@@ -786,7 +786,7 @@ def test_python_csv_only_allows_replace(mode):
     entry = _csv_entry(mode_type=mode)
     if mode == "upsert":
         entry["primary_key"] = ["order_id"]
-    with pytest.raises(ContractError, match=f"'mode_type' {mode} is not allowed for kind python-csv"):
+    with pytest.raises(ContractError, match=f"'mode_type' '{mode}' is not allowed for kind 'python-csv'"):
         parse_node(entry, "f.yml", check_reads=False)