Update outdated Rust dependencies

[dracco736-blip]

/claim #44

Bounty issue: #44

Summary

• upgrades the full direct dependency stack, including Tonic/Prost, OpenTelemetry, tracing, Tokio, and Shuttle
• migrates the server transport, reflection, OTLP exporter/provider, and protobuf build APIs
• updates the generated GitHub Actions workflow and pins actions/checkout@v6
• removes direct dependencies no longer needed after the Tonic server migration

Why

The repository remained on several outdated major dependency lines. Compatible-only lockfile bumps leave the core Tonic, OpenTelemetry, and Shuttle migrations unresolved. This change updates the full stack while preserving the service behavior.

Impact

The service builds against the current Rust gRPC and telemetry ecosystem, the reflection endpoint uses v1, and CI remains reproducible with the updated workflow generator.

Demo

Validation

• cargo fmt --all -- --check
• cargo check --all-targets --all-features
• cargo test --all-features
• cargo clippy --all-targets --all-features -- -D warnings