refactor: Replace anyhow with custom ResultExt trait for zero-allocation error handling

[zvonkok]

Remove anyhow dependency and introduce a minimal ResultExt trait with .or_panic(impl Display) method. This enables fail-fast semantics with format_args!() for zero-allocation error messages, better suited for a minimal init process.

• Add ResultExt trait in macros.rs with #[cold]/#[inline(never)] for optimized error paths
• Update execute.rs, syslog.rs to use .or_panic(format_args!(...))
• Add set_test_panic_hook() in kata_agent tests to ensure forked children exit non-zero on panic (Rust test harness catches panics)

[Copilot]

Pull request overview

This PR refactors the codebase to remove the anyhow dependency and replace it with a custom ResultExt trait for zero-allocation error handling. The changes align with the minimal init process requirements where fail-fast semantics via panics are more appropriate than error propagation.

Changes:

• Removed anyhow dependency from Cargo.toml and Cargo.lock
• Added ResultExt trait in macros.rs with .or_panic(impl Display) method using #[cold] and #[inline(never)] attributes for optimized error paths
• Converted all functions returning Result<T> to either return T directly or return nothing (unit type), panicking on errors
• Updated all tests to use panic::catch_unwind() to verify panic behavior instead of checking for Err results
• Added set_test_panic_hook() helper in kata_agent tests to ensure forked children exit with non-zero status on panic

Reviewed changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/macros.rs	Replaced must! macro with ResultExt trait providing .or_panic() method with zero-allocation error formatting
src/execute.rs	Updated foreground() and background() to panic on errors using .or_panic(format_args!(...))
src/syslog.rs	Changed poll() to panic on errors instead of returning Result
src/main.rs	Removed must! macro calls, functions now panic directly; added public export of ResultExt
src/toolkit.rs	Updated ctk() and nvidia_ctk_cdi() to panic instead of returning Result
src/smi.rs	Updated all nvidia-smi functions to panic on errors instead of returning Result
src/nvrc.rs	Changed check_daemons() to panic directly instead of returning Result
src/mount.rs	Updated all mount functions to panic using unwrap_or_else instead of returning Result
src/modprobe.rs	Changed load() to panic on errors instead of returning Result
src/kernel_params.rs	Updated parameter parsing functions to use .expect() instead of returning Result
src/kata_agent.rs	Updated kata-agent functions to panic on errors; added set_test_panic_hook() for forked test children
src/daemon.rs	Updated daemon spawning functions to panic on errors instead of returning Result
src/lockdown.rs	Changed set_panic_hook() and disable_modules_loading() to panic on errors
src/kmsg.rs	Updated kernlog_setup() and kmsg() functions to panic on errors
Cargo.toml	Removed anyhow dependency
Cargo.lock	Removed anyhow dependency and its entry

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