Add SPDX license headers to all Rust source files

[Copilot]

This PR adds the required SPDX license identifier header to all Rust source files in the repository. The header // SPDX-License-Identifier: MIT OR Apache-2.0 has been added to the top of each file to comply with licensing requirements.

Changes Made

Added the SPDX header to 13 Rust source files:

• lowell-cli/src/main.rs
• lowell-cli/src/tracing_init.rs
• lowell-cli/src/cli/mod.rs
• lowell-cli/src/cli/inspect/mod.rs
• lowell-cli/src/cli/inspect/uki.rs
• lowell-core/src/lib.rs
• lowell-core/src/formats/mod.rs
• lowell-core/src/formats/initramfs.rs
• lowell-core/src/formats/osrel.rs
• lowell-core/src/formats/pe.rs
• lowell-core/src/inspect/mod.rs
• lowell-core/src/inspect/ext.rs
• lowell-core/src/inspect/uki.rs

Verification

• ✅ Project builds successfully with cargo build
• ✅ All tests pass with cargo test
• ✅ Code formatting verified with cargo fmt
• ✅ Clippy linting passes with no warnings
• ✅ CLI functionality confirmed working

The license format follows the dual MIT/Apache-2.0 licensing as documented in the project README and matches the existing license files.

Fixes #3.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[Copilot]

@SamD2021 👋 This repository doesn't have Copilot instructions. With Copilot instructions, I can understand the repository better, work faster and produce higher quality PRs.

I can generate a .github/copilot-instructions.md file for you automatically. Click here to open a pre-filled issue and assign it to me. I'll write the instructions, and then tag you for review.

[SamD2021]

LGTM