FastEdit 0.2.2

Fixed

• Silent signature corruption in replace= fast path — fast_edit with replace=<name> no longer silently corrupts the file when the snippet omits the function signature. FastEdit now auto-prepends the signature from the AST when it's missing from the snippet — matching the design intent of replace= as a structural targeting kwarg. Previously the deterministic fast path treated a body-only snippet as the full new body, wiping the def/fn/func line and reporting success anyway. Scoped to function/method/class-like kinds; constants and other value-like targets keep their full-replacement semantics. Regression covered by tests/test_replace_without_signature.py (Python + Rust, happy path, top-marker variant).