rust-guard: dedupe unsafe output write-back and unify search scope labeling arms

[Copilot]

This PR removes duplicated unsafe buffer write-back code in Rust guard FFI entrypoints and consolidates duplicated search_code / search_commits labeling logic. The result keeps behavior the same while reducing unsafe surface area and eliminating redundant branching.

• Unsafe output write-back deduplication (src/lib.rs)

  • Added a private helper:
    • unsafe fn write_bytes_to_output(output_ptr: u32, bytes: &[u8])
  • Replaced four identical raw-pointer copy blocks in:
    • label_agent
    • label_resource
    • label_response (path-based return)
    • label_response (legacy return)

• Search tool arm consolidation (src/labels/tool_rules.rs)

  • Merged search_code and search_commits into a single match arm:
    • "search_code" | "search_commits" => { ... }
  • Unified scoped description generation via format!("{}:{}", tool_name, s_repo_id).
  • Removed the redundant fallback reassignment of baseline_scope in the prior search_commits branch.

// Before: duplicated unsafe write-back at multiple call sites
unsafe {
    let dest = slice::from_raw_parts_mut(output_ptr as *mut u8, output_bytes.len());
    dest.copy_from_slice(output_bytes);
}

// After: single documented unsafe helper
unsafe fn write_bytes_to_output(output_ptr: u32, bytes: &[u8]) {
    let dest = slice::from_raw_parts_mut(output_ptr as *mut u8, bytes.len());
    dest.copy_from_slice(bytes);
}

// Unified search tool labeling
"search_code" | "search_commits" => {
    let (s_owner, s_repo, s_repo_id) = resolve_search_scope(tool_args, &owner, &repo);
    if !s_repo_id.is_empty() {
        desc = format!("{}:{}", tool_name, s_repo_id);
        // ...
    } else {
        // ...
    }
}

[Copilot]

Pull request overview

This PR refactors the Rust GitHub guard to reduce duplicated unsafe pointer write-back code in its WASM FFI entrypoints and to consolidate duplicated labeling logic for repo-scoped search tools, while preserving existing behavior.

Changes:

• Introduced a single unsafe fn write_bytes_to_output(output_ptr, bytes) helper and replaced repeated raw-pointer slice copy blocks in label_agent, label_resource, and both label_response return paths.
• Consolidated search_code and search_commits into a single match arm in tool labeling, including unified scoped description formatting and removal of redundant baseline_scope reassignment.

Show a summary per file

File	Description
guards/github-guard/rust-guard/src/lib.rs	Deduplicates unsafe output-buffer write-back logic into a single helper used by multiple FFI entrypoints.
guards/github-guard/rust-guard/src/labels/tool_rules.rs	Unifies search tool labeling logic for search_code and search_commits into one consistent match arm.

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• Files reviewed: 2/2 changed files
• Comments generated: 0