[ahsanalidotme]

Implements the wrapper parity 0.1.1 contract (linktrail-io/workspace contracts/wrapper-parity-0.1.1.md).

Includes #12. This branch merges chore/sdk-hardening-114 (Jest suite + Android requestTrackingAuthorization → true), so #12 can be closed in favour of this PR, or merged first (this PR then shrinks to its own changes).

Changes

• Links/attribution before a listener exists. Native onLink is registered only when the first JS onLink listener subscribes (new startLinkDelivery() in the spec, iOS + Android), so the native SDK keeps a saved deferred link (persisted across launches) until JS actually receives it. Re-engagement links resolved by autoHandleLinks before then are buffered in JS (max 10, oldest dropped) and delivered once, in order, to the first listener. onAttribution keeps the last value and replays it to the first listener. Later listeners get no replays.
• Error codes: camelCase codes from native (missingApiKey, notConfigured, notALinkTrailUrl, …). Promises reject with a LinkTrailError (native message unchanged, statusCode/body for server, legacyCode = old snake_case). onError carries the same fields. The JS layer also normalises snake_case input. CHANGELOG Changed has the mapping table.
• LinkTrail.version (package version, test keeps it equal to package.json) and LinkTrail.nativeSdkVersion (native LinkTrail.version / LinkTrail.VERSION).
• Pins: already per contract (podspec ~> 0.1.0, Android io.linktrail:sdk:0.1.0; RN has no SPM manifest). No change.
• Not done: iOS setSDKIdentifier (needs iOS 0.1.1).
• Version 0.1.1, CHANGELOG, README (buffering + errors table), example updated for the new code.

Validation (local)

• npm run lint (0 errors, 3 existing deep-import warnings), npm run typecheck, npm run prepare, codegen script
• npx jest: 48 tests (22 new in __tests__/parity.test.ts)
• Example: tsc, Android assembleDebug, iOS simulator build (Xcode 27 locally needed IPHONEOS_DEPLOYMENT_TARGET=15.1 for an existing AsyncStorage pod target; CI uses macos-15)
• Native-side unit tests: not added. The module classes need a running RN host (TurboModule base classes, emitters), and the repo has no native test harness; native behaviour is covered by the example builds.

Closes #22

[ahsanalidotme]

Impact

• DB changes: none (client SDK wrapper).
• Live code changes: only takes effect when apps upgrade to linktrail-react-native@0.1.1; nothing already published changes. Backend untouched.
• Breaking for integrators: error code values change from snake_case to camelCase (legacyCode keeps the old value for one release). Apps comparing error.code === 'invalid_api_key' must update (TypeScript now flags it). Android requestTrackingAuthorization() now resolves true.
• Behaviour: native onLink is now registered only when JS subscribes, so apps that never call onLink keep the deferred link saved natively instead of having it claimed and dropped by the bridge.
• Critical prod impact: none. Ships only through a new npm version.