## Why

Running playbooks produces a `[WARNING]` on every host about the discovered Python interpreter (`/usr/bin/python3.13`) potentially changing if another interpreter is installed later. This is noisy and obscures real warnings. The current `ansible_python_interpreter: auto` setting performs discovery correctly but logs a warning each time — Ansible provides `auto_silent` specifically to suppress this.

## What Changes

- Change `ansible_python_interpreter` from `auto` to `auto_silent` in `group_vars/all.yml` to suppress the interpreter discovery warning while retaining the same auto-discovery behavior.

## Capabilities

### New Capabilities

(none)

### Modified Capabilities

- `python-bootstrap`: The interpreter discovery mode changes from `auto` to `auto_silent`, suppressing the discovery warning while preserving identical behavior.

## Impact

- `group_vars/all.yml`: Single-line change to `ansible_python_interpreter` value.
- No behavioral change — `auto_silent` performs the same discovery logic as `auto`, just without the warning.