fix: Let configured file storage reach SQLite on WASI

[krodak]

Overview

SQLiteConnectionSource currently replaces every configured WASI storage value with .memory, so .file(path:) never reaches SQLite. sqlite-nio now supports file-backed databases through the stock WASI filesystem, so this removes the obsolete workaround and passes the configured file path through.

Existing .memory behavior on WASI stays unchanged. Non-WASI code is unchanged.

Links

• GitLab sprint issue: https://gitlab.com/PassiveLogic/platform/khasm/-/work_items/24
• ClickUp task: https://app.clickup.com/t/86bbu7m45

What changed

• SQLiteConnectionSource.swift - preserve .memory storage on WASI and pass .file(path:) directly to SQLiteConnection.Storage.file.

Tested

• ~/.swiftly/bin/swiftly run swift test +6.3.3
• ~/.swiftly/bin/swiftly run swift build +6.3.3 --swift-sdk swift-6.3.3-RELEASE_wasm
• Fresh-process QuantumStorageCore persistence harness: write in one wasmtime process, read from the same file in a second process

[scottmarchant]

Great idea, thanks!