feat(raw): add non-destructive development workflow

[IAmJSD]

Summary

• preserve the original capture and typed development settings on RAW-backed layers
• apply white balance and exposure in the sensor/linear pipeline, with debounced fast previews and best-quality asynchronous apply
• reopen Camera Raw with saved values, reset to as-shot settings, and automatically open it for directly imported RAW files
• round-trip the original RAW source and settings through PSD/PSB with size and corruption guards
• keep development undoable and available in the WebAssembly application

Verification

• cargo fmt --all -- --check
• git diff --check
• cargo test -p schist-core -p schist-codec-psd -p schist-codecs-common
• cargo test -p schist-codec-psd
• cargo clippy -p schist-core -p schist-codec-psd -p schist-codecs-common -p schist-app -- -D warnings
• cargo check -p schist-app
• cargo check -p schist-app --target wasm32-unknown-unknown