feat: run commands and streams on an exec channel, reach the container engine

netOrk drove this driver's shell through the private `_send` (an
interactive PTY, stdout and stderr merged, no exit code) and opened its
own paramiko connections for Docker. napalm-device-types 2.6.0 makes the
channel public; this implements it (NetOrk/netork#765):

- `run_command()` and `open_stream()` open an exec channel on the SSH
  transport netmiko already holds: no second login, no PTY, a real exit
  status.
- `privileged=True` follows the driver's existing rules: as root the
  command runs directly; with a sudo password it goes through
  `sudo -S -p ''` and the password is written to stdin, never onto the
  command line; without one `sudo -n` fails at once instead of hanging.
- `ContainerEngineMixin` is mixed in, so `open_container_engine("docker")`
  streams the Engine API over `docker system dial-stdio`.

The existing Docker methods are unchanged. Version 0.2.0, requires
napalm-device-types >= 2.6.0.

Refs NAPALM/napalm-device-types#17

CHANGELOG.md

@@ -7,6 +7,23 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.2.0] – 2026-10-07
+
+### Added
+
+- `run_command()` and `open_stream()`, the public command channel from
+  napalm-device-types 2.6.0: an exec channel on the existing SSH transport, so
+  no PTY, separate stderr and a real exit code. `privileged=True` runs as root
+  directly, through `sudo -S` with the password on stdin (never on the command
+  line), or through `sudo -n`, which fails instead of prompting.
+- `ContainerEngineMixin`: `container_engines()` and `open_container_engine()`,
+  whose `open_api()` streams the Docker Engine API over `docker system
+  dial-stdio` (NetOrk/netork#765). The existing Docker methods are unchanged.
+
+### Changed
+
+- Requires napalm-device-types >= 2.6.0.
+
 ## [0.1.0] – 2026-05-29
 
 ### Added