Burn down SwiftLint advisory violations from 109 to 4 (#1362)

Mechanical style fixes across the enabled rule set, mostly via
swiftlint --fix (trailing_comma, comma, colon, trailing_newline,
comment_spacing, unused_closure_parameter, unneeded_break_in_switch,
opening_brace) plus hand fixes:

- non_optional_string_data_conversion (45): .data(using: .utf8)! and
  ?? Data() fallbacks replaced with the non-optional Data(_.utf8),
  including two production sites (NIP-44 HKDF info constant and the
  announce canonicalization context/nickname bytes — byte-identical
  output, only the impossible-nil handling is gone).
- switch_case_alignment: LocationChannel had a misindented closing
  brace; also repaired an --fix artifact in BLEService's .none case.
- redundant_string_enum_value: TrustLevel raw values equal to the case
  names (encoded form unchanged).
- unused_optional_binding: let _ = binds replaced with != nil / is Bool.
- static_over_final_class: PreviewView.layerClass.
- Resolved the BinaryProtocolTests TODO by documenting that 8-byte
  recipient ID truncation is the fixed wire-field size, not a bug.

The 4 remaining violations are all todo markers for a shared
test-helpers module (tracked in #1088) and one Reuse note.

Co-authored-by: jack <jackjackbits@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

localPackages/Arti/Package.swift

@@ -5,16 +5,16 @@ let package = Package(
     name: "Tor",  // Keep name "Tor" for drop-in compatibility
     platforms: [
         .iOS(.v16),
-        .macOS(.v13),
+        .macOS(.v13)
     ],
     products: [
         .library(
             name: "Tor",
             targets: ["Tor"]
-        ),
+        )
     ],
     dependencies: [
-        .package(path: "../BitLogger"),
+        .package(path: "../BitLogger")
     ],
     targets: [
         // Main Swift target
@@ -22,19 +22,19 @@ let package = Package(
             name: "Tor",
             dependencies: [
                 "arti",
-                .product(name: "BitLogger", package: "BitLogger"),
+                .product(name: "BitLogger", package: "BitLogger")
             ],
             path: "Sources",
             exclude: ["C"],
             sources: [
                 "TorManager.swift",
                 "TorURLSession.swift",
-                "TorNotifications.swift",
+                "TorNotifications.swift"
             ],
             linkerSettings: [
                 .linkedLibrary("resolv"),
                 .linkedLibrary("z"),
-                .linkedLibrary("sqlite3"),
+                .linkedLibrary("sqlite3")
             ]
         ),
         // Binary framework containing the Rust static library.
@@ -42,6 +42,6 @@ let package = Package(
         .binaryTarget(
             name: "arti",
             path: "Frameworks/arti.xcframework"
-        ),
+        )
     ]
 )

localPackages/BitFoundation/Package.swift

@@ -21,7 +21,7 @@ let package = Package(
         .target(
             name: "BitFoundation",
             dependencies: [
-                .product(name: "BitLogger", package: "BitLogger"),
+                .product(name: "BitLogger", package: "BitLogger")
             ],
             path: "Sources"
         ),

localPackages/BitFoundation/Tests/BitFoundationTests/BinaryProtocolTests.swift

@@ -46,7 +46,8 @@ struct BinaryProtocolTests {
         // Verify recipient
         #expect(decodedPacket.recipientID != nil)
         let decodedRecipientID = decodedPacket.recipientID?.trimmingNullBytes()
-        // TODO: Check if this is intended that the decoding only gets the first 8
+        // Recipient IDs are a fixed 8-byte wire field: encode pads or truncates
+        // to BinaryProtocol.recipientIDSize, so only the first 8 bytes survive.
         #expect(String(data: decodedRecipientID!, encoding: .utf8) == "abcdef01")
     }
     
@@ -294,7 +295,7 @@ struct BinaryProtocolTests {
     @Test("Create a large, compressible payload above current threshold (2048B)")
     func payloadCompression() throws {
         let repeatedString = String(repeating: "This is a test message. ", count: 200)
-        let largePayload = repeatedString.data(using: .utf8)!
+        let largePayload = Data(repeatedString.utf8)
         
         let packet = TestHelpers.createTestPacket(payload: largePayload)
         
@@ -314,7 +315,7 @@ struct BinaryProtocolTests {
     
     @Test("Small payloads should not be compressed")
     func smallPayloadNoCompression() throws {
-        let smallPayload = "Hi".data(using: .utf8)!
+        let smallPayload = Data("Hi".utf8)
         let packet = TestHelpers.createTestPacket(payload: smallPayload)
         let encodedData = try #require(BinaryProtocol.encode(packet), "Failed to encode small packet")
         let decodedPacket = try #require(BinaryProtocol.decode(encodedData), "Failed to decode small packet")
@@ -362,7 +363,7 @@ struct BinaryProtocolTests {
         var encodedSizes = Set<Int>()
         
         for payload in payloads {
-            let packet = TestHelpers.createTestPacket(payload: payload.data(using: .utf8)!)
+            let packet = TestHelpers.createTestPacket(payload: Data(payload.utf8))
             let encodedData = try #require(BinaryProtocol.encode(packet), "Failed to encode packet")
             
             // Verify padding creates standard block sizes up to configured limit (no 4096 bucket currently)

localPackages/BitFoundation/Tests/BitFoundationTests/TestHelpers.swift

@@ -54,13 +54,13 @@ final class TestHelpers {
         type: UInt8 = 0x01,
         senderID: PeerID = PeerID(str: UUID().uuidString),
         recipientID: PeerID? = nil,
-        payload: Data = "test payload".data(using: .utf8)!,
+        payload: Data = Data("test payload".utf8),
         signature: Data? = nil,
         ttl: UInt8 = 3
     ) -> BitchatPacket {
         return BitchatPacket(
             type: type,
-            senderID: senderID.id.data(using: .utf8)!,
+            senderID: Data(senderID.id.utf8),
             recipientID: recipientID?.id.data(using: .utf8),
             timestamp: UInt64(Date().timeIntervalSince1970 * 1000),
             payload: payload,