Refactor command execution and buffer management.
- `CommitFormula` now defaults to targeting `_Measure` .
- `CommitFormula` no longer automatically clears the buffer; buffer
clearing is now handled by keymap sequences.
- Added `ClearBufferCmd` to the command registry.
- Updated `AddFormulaCmd` to support optional target category.
- Added `SetBuffer` effect to allow clearing buffers.
Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/gemma-4-26B-A4B-it-GGUF:UD-Q5_K_XL)
Move tests from the monolithic tests.rs into #[cfg(test)] mod tests
blocks in each command module. Shared test helpers live in
mod.rs::test_helpers.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Executed-By: fido
