Use Record APIs in nu-protocol/nu-engine (#10917)

# Description
Consequences of #10841

This does not yet make the assumption that columns are always
duplicated. Follow the existing logic here

- Use saner record API in `nu-engine/src/eval.rs`
- Use checked record construction in `nu-engine/src/scope.rs`
- Use `values` iterator in `nu-engine/src/scope.rs`
- Use `columns` iterator in `nu_engine::get_columns()`
- Start using record API in `value/mod.rs`
- Use `.insert` in `eval_const.rs` Record code
- Record API for `eval_const.rs` table code

# User-Facing Changes
None

# Tests + Formatting
None

crates/nu-protocol/src/eval_const.rs

@@ -287,15 +287,7 @@ pub fn eval_constant(
             for (col, val) in fields {
                 // avoid duplicate cols.
                 let col_name = value_as_string(eval_constant(working_set, col)?, expr.span)?;
-                let pos = record.cols.iter().position(|c| c == &col_name);
-                match pos {
-                    Some(index) => {
-                        record.vals[index] = eval_constant(working_set, val)?;
-                    }
-                    None => {
-                        record.push(col_name, eval_constant(working_set, val)?);
-                    }
-                }
+                record.insert(col_name, eval_constant(working_set, val)?);
             }
 
             Ok(Value::record(record, expr.span))
@@ -323,11 +315,9 @@ pub fn eval_constant(
                 for expr in val {
                     row.push(eval_constant(working_set, expr)?);
                 }
+                // length equality already ensured in parser
                 output_rows.push(Value::record(
-                    Record {
-                        cols: output_headers.clone(),
-                        vals: row,
-                    },
+                    Record::from_raw_cols_vals(output_headers.clone(), row),
                     expr.span,
                 ));
             }

crates/nu-protocol/src/value/mod.rs

@@ -3113,7 +3113,7 @@ impl Value {
             }
             (lhs, Value::List { vals: rhs, .. }) => Ok(Value::bool(rhs.contains(lhs), span)),
             (Value::String { val: lhs, .. }, Value::Record { val: rhs, .. }) => {
-                Ok(Value::bool(rhs.cols.contains(lhs), span))
+                Ok(Value::bool(rhs.contains(lhs), span))
             }
             (Value::String { .. } | Value::Int { .. }, Value::CellPath { val: rhs, .. }) => {
                 let val = rhs.members.iter().any(|member| match (self, member) {
@@ -3161,7 +3161,7 @@ impl Value {
             }
             (lhs, Value::List { vals: rhs, .. }) => Ok(Value::bool(!rhs.contains(lhs), span)),
             (Value::String { val: lhs, .. }, Value::Record { val: rhs, .. }) => {
-                Ok(Value::bool(!rhs.cols.contains(lhs), span))
+                Ok(Value::bool(!rhs.contains(lhs), span))
             }
             (Value::String { .. } | Value::Int { .. }, Value::CellPath { val: rhs, .. }) => {
                 let val = rhs.members.iter().any(|member| match (self, member) {