c7d7bb5520
- Removed `output_mode` parameter from grep tool, consolidating all output to content mode with file grouping and match headers. - Renamed grep context parameters from `context_pre`/`context_post` to `pre`/`post` for improved clarity. - Removed `n` (line numbers) parameter from grep tool as line numbers are now always displayed. - Reformatted grep output to display numbered matches with file paths, line numbers, and context lines with consistent alignment. - Introduced `SearchParams` struct in Rust grep implementation to simplify parameter passing and improve code maintainability. - Made `normalize_env_key` function const-eligible for compile-time evaluation in shell module.