Add `open_wg_iface()` to create, configure and remove one WireGuard
interface inside a pinned bindspace through pyroute2.
Deats,
- validate listen/dial bearer policy before kernel side effects
- configure local addresses, private key, listen port and peers
- fill an omitted dial endpoint from the selected tunnel bearer
- clean partial synchronous failures before returning to Trio
- shield owned interface creation and teardown from cancellation
Prompt-IO: ai/prompt-io/opencode/20260826T003430Z_6dd39da0_prompt_io.md
(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))
Gud Boi