Adopt root-level tsswift app layout

Move the app payload under swift/ while keeping git, package.json, and .smartconfig.json at the repo root. This standardizes the Swift app setup so build, test, run, and watch workflows match the other repos.

swift/Tests/PairingPayloadParserTests.swift

@@ -0,0 +1,28 @@
+import XCTest
+@testable import IDPGlobal
+
+final class PairingPayloadParserTests: XCTestCase {
+    func testParsesStructuredPairingPayload() throws {
+        let payload = "idp.global://pair?token=swiftapp-demo-berlin&origin=code.foss.global&device=Safari%20on%20Berlin%20MBP"
+
+        let context = try PairingPayloadParser.parse(payload)
+
+        XCTAssertEqual(context.deviceName, "Safari on Berlin MBP")
+        XCTAssertEqual(context.originHost, "code.foss.global")
+        XCTAssertEqual(context.tokenPreview, "berlin")
+    }
+
+    func testParsesManualFallbackPayload() throws {
+        let context = try PairingPayloadParser.parse("manual pair token 1234567890")
+
+        XCTAssertEqual(context.deviceName, "Manual Session")
+        XCTAssertEqual(context.originHost, "code.foss.global")
+        XCTAssertEqual(context.tokenPreview, "567890")
+    }
+
+    func testRejectsInvalidPayload() {
+        XCTAssertThrowsError(try PairingPayloadParser.parse("https://example.com")) { error in
+            XCTAssertEqual(error as? AppError, .invalidPairingPayload)
+        }
+    }
+}