Claude review: rust: devres: add DevresLt for ForLt-aware device resource access

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

Patch Review

This is the core new abstraction. The `DevresLt` design is clean:

```rust
pub struct DevresLt<F: ForLt>(Devres<F::Of<'static>>)
where
    F::Of<'static>: Send;
```

The `new()` method's use of `pin_init_from_closure` to cast the slot pointer is sound — lifetimes don't affect layout:

```rust
let data = unsafe {
    pin_init::pin_init_from_closure::<F::Of<'static>, E>(move |slot| {
        data.__pinned_init(slot.cast())
    })
};
```

The `DevresGuard` type cleanly wraps `RevocableGuard` with lifetime shortening:

```rust
impl<'a, F: CovariantForLt> core::ops::Deref for DevresGuard<'a, F> {
    type Target = F::Of<'a>;
    fn deref(&self) -> &Self::Target {
        F::cast_ref(&*self.0)
    }
}
```

**Design question:** `access_with` and `try_access_with` provide `&'a F::Of<'a>` (non-pinned), while the auxiliary `registration_data_with` provides `Pin<&'a F::Of<'a>>`. This is consistent with the existing `Devres::access` API (which returns `&T`, not `Pin<&T>`), but it does mean types that require `Pin` for access (e.g., types with pinned `Mutex` fields whose methods require `Pin<&Self>`) can't use `DevresLt`'s closure accessors directly. If this becomes needed, a pinned variant could be added later. Not a blocker for this series since the current consumers (`Bar`, `IoMem`) don't need pinning.

**Minor note:** `try_access_with` accesses `self.0.data()` which calls the private `Devres::data()` method. This works because `DevresLt` is in the same module (`devres.rs`).

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Generated by Claude Code Patch Reviewer