feat(swift-sdk): add ByteLystPlatform unified entry point + 5 new test files (4.1)
New source:
- ByteLystPlatform.swift — unified entry point wiring all services
(config, client, telemetry, flags, killSwitch, crashReporter, keychain, auditLog, auth)
- BLKeychainAccessor — convenience wrapper binding BLKeychain to a bundleId
- start(userId:) / stop() lifecycle for telemetry + flags + killSwitch
New tests (5 files, ~25 test cases):
- ByteLystPlatformTests — init, start/stop, idempotency, keychain accessor
- BLPlatformConfigTests — default + custom init
- BLKillSwitchClientTests — default state, reset
- BLFeatureFlagClientTests — empty flags, unknown key, stop
- BLTelemetryClientTests — installId stability, session rotation, track/flush
Also: add .build/ and .swiftpm/ to .gitignore
933390e89b