Semamerge

Catches the merge conflicts Git misses by comparing abstract syntax trees across branches. Exposes four tools: check_merge_safety for quick pre-merge risk scoring, analyze_branches for full three-way semantic diffs, list_semantic_changes to see what actually changed in function signatures and exports, and analyze_file_pair for diving into specific files. Works on TypeScript and JavaScript codebases by parsing with tree-sitter, extracting types and interfaces and function signatures, then cross-referencing changes to find incompatibilities like a branch removing an export while another branch imports it, or one branch changing a return type while another branch depends on the old shape. Runs via stdio without checking out branches.