v0.1.0 of keepass_web

KeePass KDBX SDK for the web; implements package:keepass APIs over a WASM Worker bridge. Changelog excerpt: - First publishable release of the web SDK. - KeePassWebApiimplements the platform-agnostic KeePassApifrom package:keepass, backed by a WASM module hosted in a Web Worker. - WorkerBridge, WorkerError, and WebUSB YubiKey challenge-response helpers exposed for app integration. - Internal package:keepass/src/...import replaced with the public package:keepass/keepass.dartentry point. - WebFileStorageProvider(which depended on package:keepass_ui) is relocated to the reference exampl[...]