feat: Add xtask automation crate and improve project compatibility

- Add xtask crate for development automation
  - Build, clippy, format, docs, header-check/fix, test commands
  - Hardware test image generation support
  - Pre-commit checks and CI/CD integration
- Pin to nightly-2024-09-17 toolchain for stability
- Fix dependency conflicts and improve Hubris compatibility
  - Downgrade cortex-m to 0.7.5 for Hubris compatibility
  - Clean up embedded-hal version conflicts
  - Remove unnecessary runtime dependencies
- Fix clippy warnings for better code quality
  - Add numeric literal separators for readability
  - Address formatting and style issues
- Update workspace configuration
  - Add rust-toolchain.toml for consistent toolchain
  - Update rust-version to match nightly (1.83.0)
  - Configure cargo aliases for xtask commands
- Improve build system and CI readiness
  - Compatible with modern Rust embedded workflows
  - Follows Caliptra MCU automation patterns
  - Ready for Oxide Hubris integration

Author: rusty1968

.cargo/config.toml

@@ -1,3 +1,6 @@
+[alias]
+xtask = "run --package xtask --target x86_64-unknown-linux-gnu --"
+
 [target.thumbv7em-none-eabihf]
 rustflags = [
   "-C", "link-arg=-Map=firmware.map"