Release checklist: v0.4.12

[github-actions]

This is a checklist to track the release of v0.4.12.

Core build (this repo):

• GitHub Release (add release notes and make public)
• New version released on crates.io
• Verify Android aar released on Maven Central
• Cocoapod released

SQLite + powersync bundles:

• react-native-quick-sqlite: Update core extension to 0.4.12 react-native-quick-sqlite#108
• wa-sqlite build: Update core extension wa-sqlite#65
• sql.js dev adapter: Update core extension to 0.4.12 powersync-sql-js#24

User-facing SDK updates:

• powersync.dart (see instructions in this file):
• powersync-js (directly update node, op-sqlite and capacitor packages; upgrade dependencies on rnqs, wa-sqlite and sql-js in packages and demos): Update PowerSync core extension powersync-js#927
• kotlin (update in libs.versions.toml): Update core extension, prepare release powersync-kotlin#338
• swift (update in Package.swift):
• native (update in Cargo.toml): Update core extension to 0.4.12 powersync-native#12
• dotnet (update Tools/Setup/Setup.cs): Update core extension, include Windows arm binary powersync-dotnet#55