Add Swift TII loading and parameter introspection

[scarmuega]

Summary

• load TII documents from file URLs, JSON bytes, strings, and parsed JSON
• expose transactions, parties, profiles, environment schemas, components, and recursive parameter types
• preserve unknown schemas and recursive named references without guessing
• add canonical transfer and complex fixtures with pinned source attribution

Verification

• swift build --configuration debug
• swift format lint --strict --recursive Sources Tests Package.swift
• swift test --filter Tx3SDKTests --parallel (14 tests passed)
• swift build --package-path examples/consumer
• xcodebuild -scheme tx3-swift-sdk -destination 'platform=iOS Simulator,name=iPhone 17 Pro,OS=26.2' test
• The CI-pinned iPhone 16 Pro / iOS 18.5 runtime was unavailable locally; the installed iPhone 17 Pro / iOS 26.2 simulator passed.

[scarmuega]

Review readiness withdrawn. This plan requires an explicit decision; do not merge additional work.