style: fix swift-format lint warnings

- Break long lines under 120-char limit
- Fix indentation in KeyedEncodingContainer initializers
- Fix line breaks in multiline expressions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: g-cqd

Sources/CSVCoder/Encoder/CSVRowEncoder.swift

@@ -234,12 +234,14 @@ nonisolated struct CSVKeyedEncodingContainer<Key: CodingKey>: KeyedEncodingConta
     ) -> KeyedEncodingContainer<NestedKey> {
         switch configuration.nestedTypeEncodingStrategy {
         case .error:
-            return KeyedEncodingContainer(CSVPoisonKeyedEncodingContainer<NestedKey>(
-                error: CSVEncodingError.unsupportedType(
-                    "Nested containers are not supported in CSV. Configure nestedTypeEncodingStrategy to enable."
-                ),
-                codingPath: codingPath + [key],
-            ))
+            return KeyedEncodingContainer(
+                CSVPoisonKeyedEncodingContainer<NestedKey>(
+                    error: CSVEncodingError.unsupportedType(
+                        "Nested containers are not supported in CSV. Configure nestedTypeEncodingStrategy to enable."
+                    ),
+                    codingPath: codingPath + [key],
+                )
+            )
 
         case .flatten(let separator):
             let nestedPrefix = prefixedKey(key) + separator
@@ -253,12 +255,14 @@ nonisolated struct CSVKeyedEncodingContainer<Key: CodingKey>: KeyedEncodingConta
 
         case .codable,
             .json:
-            return KeyedEncodingContainer(CSVPoisonKeyedEncodingContainer<NestedKey>(
-                error: CSVEncodingError.unsupportedType(
-                    "JSON/Codable nested encoding requires using encode(_:forKey:) with the nested value directly"
-                ),
-                codingPath: codingPath + [key],
-            ))
+            return KeyedEncodingContainer(
+                CSVPoisonKeyedEncodingContainer<NestedKey>(
+                    error: CSVEncodingError.unsupportedType(
+                        "JSON/Codable nested encoding requires using encode(_:forKey:) with the nested value directly"
+                    ),
+                    codingPath: codingPath + [key],
+                )
+            )
         }
     }
 
@@ -299,12 +303,16 @@ nonisolated struct CSVKeyedEncodingContainer<Key: CodingKey>: KeyedEncodingConta
     }
 
     mutating func encodeIfPresent(_ value: Double?, forKey key: Key) throws {
-        let formatted = try value.map { try CSVValueFormatter.formatNumber($0, strategy: configuration.numberEncodingStrategy) }
+        let formatted = try value.map {
+            try CSVValueFormatter.formatNumber($0, strategy: configuration.numberEncodingStrategy)
+        }
         storage.setValue(formatted ?? "", forKey: prefixedKey(key))
     }
 
     mutating func encodeIfPresent(_ value: Float?, forKey key: Key) throws {
-        let formatted = try value.map { try CSVValueFormatter.formatNumber(Double($0), strategy: configuration.numberEncodingStrategy) }
+        let formatted = try value.map {
+            try CSVValueFormatter.formatNumber(Double($0), strategy: configuration.numberEncodingStrategy)
+        }
         storage.setValue(formatted ?? "", forKey: prefixedKey(key))
     }
 

Sources/CSVCoder/Encoder/CSVSingleValueEncoder.swift

@@ -155,10 +155,12 @@ nonisolated struct CSVThrowingKeyedEncodingContainer<Key: CodingKey>: KeyedEncod
         keyedBy _: NestedKey.Type,
         forKey _: Key
     ) -> KeyedEncodingContainer<NestedKey> {
-        KeyedEncodingContainer(CSVPoisonKeyedEncodingContainer<NestedKey>(
-            error: CSVEncodingError.unsupportedType("Nested containers are not supported"),
-            codingPath: codingPath,
-        ))
+        KeyedEncodingContainer(
+            CSVPoisonKeyedEncodingContainer<NestedKey>(
+                error: CSVEncodingError.unsupportedType("Nested containers are not supported"),
+                codingPath: codingPath,
+            )
+        )
     }
 
     mutating func nestedUnkeyedContainer(forKey key: Key) -> UnkeyedEncodingContainer {
@@ -205,7 +207,8 @@ nonisolated struct CSVSingleValueEncodingContainer: SingleValueEncodingContainer
     }
 
     mutating func encode(_ value: Bool) throws {
-        storage.setValue(CSVValueFormatter.formatBool(value, strategy: configuration.boolEncodingStrategy), forKey: currentKey)
+        let formatted = CSVValueFormatter.formatBool(value, strategy: configuration.boolEncodingStrategy)
+        storage.setValue(formatted, forKey: currentKey)
     }
 
     mutating func encode(_ value: String) throws {

Tests/CSVCoderTests/CSVConcurrencyStressTests.swift

@@ -51,8 +51,7 @@ struct CSVConcurrencyStressTests {
         #expect(results.count == taskCount)
 
         for csv in results {
-            let lines = csv
-                .components(separatedBy: "\n")
+            let lines = csv.components(separatedBy: "\n")
                 .filter { !$0.isEmpty }
 
             // First line must be the header.