feat: Add Rust tee-launcher crate

[barakeinav1]

Background

The current Python-based TEE launcher (tee_launcher/launcher.py) needs to be replaced with a Rust implementation for better performance, type safety, and integration with the MPC node codebase. This is the first step in the Rust launcher migration (see #2262 for the full plan).

User Story

As a developer, I want the Rust launcher crate available in the workspace so that deployment configs, CI, test assets, and localnet scripts can be built on top of it in follow-up PRs.

Acceptance Criteria

• New crates/tee-launcher/ crate with Rust binary
• Validates MPC image hashes against the contract's approved list
• Extends RTMR3 with the validated image digest
• Writes MPC node config to shared volume and launches via Docker Compose
• Uses reqwest 0.12 with bundled webpki-roots for reproducible builds
• Compiles with cargo check --locked -p tee-launcher
• Python launcher in tee_launcher/ preserved (separate removal in [rust-launcher] Remove old Python launcher #2615)

Resources & Additional Notes

• PR: feat: add Rust tee-launcher crate #2621
• Split from chore: port node launcher to Rust #2618 (full Rust launcher PR) for easier review
• Follow-up PRs will add: deployment configs/Dockerfile, CI changes, test assets, localnet scripts