fix: ADR-0036 — name the offending value for natural-order SQL INSERTs

A no-column-list (natural-order / Form B) SQL INSERT that hit a UNIQUE/
CHECK violation degraded to the neutral "that value" because
user_value_for_column only resolved the offending value for the explicit-
column-list form. Extend user_value_for_column_with_schema to map each
VALUES position to the schema's columns in declaration order (ALL columns
— advanced-mode Form B auto-fills nothing, so every column has a value),
single-row only (multi-row stays ambiguous). Closes the Phase 1 carryover
gap so the error names the real value either way.

Tests: 1948 passing (+1), 0 failed, 0 skipped, 1 ignored; clippy clean.

src/runtime.rs

@@ -1572,9 +1572,11 @@ fn user_value_for_column(command: &Command, column: &str) -> Option<crate::dsl::
             .map(|(_, v)| v.clone()),
         // ADR-0036 Phase 1: a single-row literal SQL INSERT retains its
         // captured literals, so a constraint error can name the real
-        // value. Explicit column list only here (natural order needs the
-        // schema); multi-row is skipped (which row conflicted is
-        // ambiguous) — both degrade to the neutral "that value".
+        // value. Explicit column list resolves here (sync, no schema);
+        // the natural-order (no-column-list) form is resolved in
+        // `user_value_for_column_with_schema` (it needs the schema to map
+        // position → column). Multi-row is skipped (which row conflicted
+        // is ambiguous) — it degrades to the neutral "that value".
         Command::SqlInsert {
             listed_columns,
             literal_rows,
@@ -1639,6 +1641,29 @@ async fn user_value_for_column_with_schema(
         let idx = natural_cols.iter().position(|c| *c == column)?;
         return values.get(idx).cloned();
     }
+    // ADR-0036 Phase 1 follow-up: a no-column-list (natural-order) SQL
+    // INSERT also names the offending value. Each VALUES position maps to
+    // the schema's columns in declaration order — and unlike the DSL
+    // `Insert` short form above, ALL columns are mapped (advanced-mode
+    // Form B auto-fills nothing, so the user supplies a value for every
+    // column; `do_sql_insert` validates against the same full mapping).
+    // Single-row only — which row of a multi-row insert conflicted is
+    // ambiguous, so it degrades to the neutral "that value".
+    if let Command::SqlInsert {
+        listed_columns,
+        literal_rows,
+        ..
+    } = command
+        && listed_columns.is_empty()
+        && literal_rows.len() == 1
+    {
+        let desc = database
+            .describe_table(table.to_string(), None)
+            .await
+            .ok()?;
+        let idx = desc.columns.iter().position(|c| c.name == column)?;
+        return literal_rows[0].get(idx).cloned().flatten();
+    }
     None
 }