bug: Shell escape (!) in --tui mode does not yield terminal stdin to interactive subprocesses

### Checks
- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my
issue
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again
### Operating system
Ubuntu 24.04 LTS on WSL2 (kernel 6.6.87.2-microsoft-standard-WSL2)
### Expected behaviour
When running an interactive command via the `!` shell escape in `--tui` mode (e.g. `!my-script` where the script uses `read -r` to wait for user input), the CLI
should temporarily:
1. Save the TUI terminal state
2. Restore the terminal to cooked mode
3. Yield stdin to the child process
4. Re-enter TUI/raw mode when the subprocess exits
This is the standard pattern used by other TUI applications that support shell escapes (vim `:!cmd`, less `!cmd`, htop, etc.).
The non-TUI `kiro-cli chat` mode handles `!` commands correctly — this is specific to `--tui`.
### Actual behaviour
In `--tui` mode, the TUI retains raw terminal control and does not yield stdin to the subprocess. This causes two failure modes depending on how the script reads
input:
1. **`read -r` (from stdin):** Gets immediate EOF — the script doesn't wait for input and exits instantly
2. **`read -r &2
read -r
echo "Done!" >&2
```
Save as `~/bin/test-interactive`, `chmod +x`.
2. Start kiro-cli in TUI mode:
```bash
kiro-cli chat --tui
```
3. Run the script via shell escape:
```
> !test-interactive
```
**Result:** Script either exits instantly (stdin EOF) or hangs forever (/dev/tty blocked by TUI). Terminal becomes unresponsive to Ctrl+C.
4. Compare with non-TUI mode:
```bash
kiro-cli chat
> !test-interactive
```
**Result:** Works correctly — waits for Enter, then prints "Done!".
### Real-world impact
A voice recording script that uses `read -r` to wait for Enter (to stop recording) cannot be used via `!` in TUI mode. The recording either captures nothing
(immediate exit) or requires force-killing the process.
### Additional context
- PR #1340 (`feat(tools): execute_bash uses PTY for shell integrations`) addressed a related issue for the `execute_bash` tool but was closed without merging.
- The fix pattern is well-established: save terminal state → `tcsetattr` to restore cooked mode → `fork`/`exec` with inherited stdin/stdout/stderr → `waitpid` →
restore TUI raw mode. This is how ncurses `endwin()`/`refresh()` and crossterm `disable_raw_mode()`/`enable_raw_mode()` handle it.
### Environment
```yaml
[q-details]
version = "1.28.1"
hash = "fc92565d6f51c1708e92500b2b2bcc4a424f5705"
date = "2026-03-21T05:18:11.590914Z"
variant = "minimal"
[system-info]
chip = "Intel(R) Core(TM) Ultra 7 265H"
total-cores = 16
memory = "15.35 GB"
[system-info.os.linux]
kernel_version = "6.6.87.2-microsoft-standard-WSL2"
id = "ubuntu"
name = "Ubuntu"
pretty_name = "Ubuntu 24.04 LTS"
version_id = "24.04"
[environment]
os = "Linux"
shell-path = "/bin/bash"
in-wsl = true
```