get_rust_module() was called outside the try block in GitStatusTool/GitDiffTool/GitLogTool.execute(), so on installs without the compiled openjarvis-rust extension (e.g. plain pip installs, where openjarvis-rust is a uv-only group since #624) the ImportError escaped uncaught instead of degrading. Move the call inside try and fall back to the git CLI via the existing _run_git helper on ImportError, matching the fallback git_log already had. Adds regression tests covering the fallback path for all three tools.
Co-authored-by: Elliot Slusky <elliot@slusky.com>