Use Rust 1.85 for edition2024 support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Jonathan D.A. Jewell

Dockerfile

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: MIT OR Palimpsest-0.6
 # SPDX-FileCopyrightText: 2025 ECHIDNA Project Contributors
 
-FROM rust:1.83-slim-bookworm AS builder
+FROM rust:1.85-slim-bookworm AS builder
 
 WORKDIR /build