Claude review: rust: types: Add Ownable/Owned types

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

This is the central patch. The design is sound.

**Minor typo** at line 859 (in `Owned::from_raw`):
```rust
// INVARIANT: By funvtion safety requirement we satisfy the first invariant of `Self`.
```
"funvtion" should be "function".

**Trailing `//` markers**: Throughout this patch and others, there are trailing `//` comments used as rustfmt anchors to force one-item-per-line formatting:
```rust
use core::{
    mem::ManuallyDrop,
    ops::{
        Deref,
        DerefMut, //
    },
    pin::Pin,
    ptr::NonNull, //
};
```
This is a known pattern in the kernel Rust tree, but it's still worth noting that it creates visual noise. This is a project-level style decision and not a blocker.

**`Ownable::release` safety**: The trait is safe to implement but `release` is `unsafe fn` — this is the correct pattern. The safety requirement ("callers must ensure exclusive ownership transferable to `release`") is well-documented. The `Owned<T>::drop` impl satisfies this because `&mut self` in `drop` guarantees exclusive access.

**`DerefMut` bound on `Unpin`**: The decision to only provide `DerefMut` for `T: Unpin` is correct — it prevents moving out of pinned types through `&mut T`.

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Generated by Claude Code Patch Reviewer