Summary

Fix the Docker Build Check failure introduced after the dependency refresh to sysinfo 0.39.2, which requires Rust 1.95 while the Docker builder image was still pinned to Rust 1.88.

Changes

• Update the Docker builder image from rust:1.88-slim to rust:1.95-slim.
• Fix the Dockerfile FROM ... AS casing warning reported by buildx.
• Declare the crate MSRV explicitly with rust-version = "1.95".
• Align Debian/Launchpad packaging Rust and Cargo requirements from 1.92 to 1.95 so packaging paths fail early with the correct requirement instead of reaching dependency resolution failures later.

Build Check Note

The regular CI Build Check runs cargo build --release --bin all-smi first and then cargo build --no-default-features --lib. Those two can fail independently because the library-only build compiles a different feature set. The current Docker failure is separate: the Dockerfile only runs the binary release build, and it failed before compilation because Cargo rejected sysinfo 0.39.2 on rustc 1.88.

Validation

• cargo metadata --format-version 1 --locked --no-deps
• cargo fmt --check
• git diff --check
• LIBRARY_PATH=/home/inureyes/Development/backend.ai/all-smi/target/local-lib cargo build --release --bin all-smi
• LIBRARY_PATH=/home/inureyes/Development/backend.ai/all-smi/target/local-lib cargo build --no-default-features --lib
• LIBRARY_PATH=/home/inureyes/Development/backend.ai/all-smi/target/local-lib cargo clippy -- -D warnings

Local Docker validation was attempted with docker build --progress=plain --target builder -t all-smi-builder-msrv-check ., but this environment cannot access /var/run/docker.sock, so the Docker-specific verification must be provided by GitHub Actions after merge.