feat: bang (!) batch commands — shell exec bypassing model, zero tokens

[alecuba16]

Summary

Adds bang (!) batch command support — commands prefixed with ! execute directly in the shell, bypassing the model entirely (zero tokens consumed).

Features

• ! <command> → runs shell command, shows output in transcript
• !! <command> → multi-line mode (pastes output into input buffer)
• Works in plan mode (blocked with warning)
• Output rendered via render_bang_display_lines()
• Intercept in main.rs main loop (was dead code in App::run)
• Render output when transcript empty (transcript_empty includes display_messages.is_empty())

Files Changed (18 files)

• src-rust/crates/cli/src/main.rs — bang intercept in main loop
• src-rust/crates/tui/src/render.rs — render_bang_display_lines() + bang output rendering
• src-rust/crates/tui/src/app.rs — bang command state handling
• src-rust/crates/tui/src/input.rs — bang command input parsing
• src-rust/crates/core/src/lib.rs — bangCommands.enabled setting
• docs/commands.md — documentation
• FEATURE_DESIGN_batch_commands_no_model.md — design doc

Note

Part of 5-PR set. Shares app.rs, render.rs, main.rs with other PRs. Consolidated from 2 branches (1 feat + 1 fix).

[alecuba16]

Closing in favor of consolidated group branches. The changes from this PR have been merged into a functional group branch.