Bazelization

[bniladridas]

Summary

• Adds Bazel support to the Rust codebase using Bzlmod, rules_rust, and crate_universe.
  What changed
• Integrated Bazel via Bzlmod with rules_rust and crate_universe for dependency management.
• Fixed the rav1e build script by wiring required environment variables.
• Verified Bazel builds for supported crates.
  Known limitations
• zune-jpeg fails under Bazel due to unsafe NEON calls.
• Full builds involving zune-jpeg should continue to use Cargo for now.
  Notes
• Bazel setup is otherwise complete and functional.
• Follow-up work may be needed to address zune-jpeg’s NEON issues under Bazel.

[harper-maintainer]

Upstream: bazelbuild/rules_rust
Implemented in #80
Tracked by #81