fix: restore browser wasm build without sqlite persistence

[manuelmauro]

Summary

• restore wasm32-unknown-unknown builds by removing SQLite and filesystem deps from the browser target
• use an in-memory persistence fallback on wasm while keeping native SQLite persistence unchanged
• add wasm packaging coverage to CI and pin wasm-bindgen-cli in release builds

Changes

• move dirs and rusqlite behind cfg(not(target_arch = "wasm32"))
• enable browser RNG support for wasm via getrandom's wasm_js feature
• add a wasm Database implementation backed by in-memory settings/score history
• make GameSettings, ScoreRecord, and ScoreHistory clonable for the wasm fallback
• add a CI job that builds release wasm, runs wasm-bindgen, and smoke-tests the packaged web bundle
• pin wasm-bindgen-cli in release workflow to match the project's wasm-bindgen version

Validation

• cargo check
• cargo check --target wasm32-unknown-unknown
• cargo build --target wasm32-unknown-unknown
• local release-style wasm packaging smoke test