feat: add neovim text editor

docs(changelog): finalize v1.0.1 release notes

v1.0.0: Professional Rust development container for desktop and embed…

…ded (ARM Cortex-M/A) development

feat: initial dev_container_rust (v1.0.0-rc1)

Rust development container for desktop and embedded development.

- Ubuntu 24.04 base (pinned by digest), multi-arch amd64+arm64
- Rust 1.94.0 stable via rustup (rustc, cargo, rustfmt, clippy,
  rust-analyzer, llvm-tools-preview)
- Embedded: 5 bare-metal thumb targets + armv7 Linux cross target
- probe-rs for embedded flashing/debugging (replaces OpenOCD)
- cargo-binstall, cargo-generate, cargo-expand, sccache
- mold fast linker, GDB, LLDB, Valgrind, gdb-multiarch
- ARM Linux cross-compiler for STM32MP135F (Cortex-A7)
- Runtime-adaptive user identity via entrypoint.sh
- CI workflows for build verification and GHCR publishing
- Single image only (apt Rust 1.75 too far behind stable)

Verified: nerdctl rootless build + smoke test passed (Ubuntu VM amd64).