Rust Settings and notification shade source checkpoint

Integrated source base: 8d231e7b (2026-09-24). The opt-in Rust client consumes the already packaged k230-settings command and private notification broker through the bounded ServiceWorker; no blocking service I/O runs in a Wayland touch callback. The shade renders broker history and its separately redacted preview, now with the broker-supplied app icon when available. Settings renders reported network, brightness, keyboard, and motion capability states, including unavailable labels. Power actions require the backend’s confirmation token, preserve it when the work queue is full, and expire its touch target by deadline. Finger scrolling follows a touch in the notification list; a horizontal swipe dismisses an eligible row. An upward swipe above the list closes the shade, preserving the separate on-device shade-close hotfix. Opening Settings expands the mapped touch region to the full output.

Host verification from nix/rust-shell-client: cargo fmt --all, cargo clippy --offline --lib --bin k230-shell-rust -- -D warnings, cargo test --offline -q, and git diff --check passed for the final source checkpoint. Cargo test covered 27 library, 6 binary, 10 appearance, 5 background, and 8 service-data tests. Tests cover bounded panel targets, cancelled tap/scroll distinction, power gating/token expiry, error visibility, shade close versus history scroll, Settings input geometry, and a named icon in the broker preview. These are source and host checks only.

The exact combined runtime-source commit 5e70fa8f736b58bcf3512448c6c9da8290cb8d0f cross-built with nix build .#handheld-shell-rust --max-jobs 1 --cores 4 --no-link --print-out-paths: derivation /nix/store/kqm5mibhhij1h7yjzr6mzzr72kzghw3g-k230-shell-rust-riscv64-unknown-linux-gnu-0.1.0.drv, output /nix/store/25x514z4808av6mq4j6bh5iyxlwjfc7b-k230-shell-rust-riscv64-unknown-linux-gnu-0.1.0. The derivation’s source is /nix/store/kbigbbsmg2nh9qxqxmn13aa3h4xfa8cp-rust-shell-client; src/main.rs and src/service_ui.rs SHA256 values match git show 5e70fa8f (1320e4512dd96ec174d45edde1d43db0497ce9bd73075736d84279d43331e4a7 and ec598ebeb8f6302e906875a6a3ca80378733fc96dd7bf9008fedeb9469c6b162). The subsequent preview-icon source commit is host checked but not in this exact target package; it needs inclusion in the integrated image build.

Remaining gates: paired compositor/client QEMU touch and service fixture showing shade history/preview, Settings unavailable/writable controls, notification actions, and confirmation cancellation; physical finger and display review on 568×1232 glass. The current device image build and board are operated separately by the coordinator. No task requiring those checks is claimed complete here.