[roll] Roll fuchsia [ksync] Transition to Pinned Locks and Lockdep in Userspace

Transition the ksync API to support pinned locks and compile-time lock
validation using the new lockdep crate.

This commit refactors the userspace implementation:
- Introduce RawLock trait to abstract the underlying platform lock.
- Implement RawLock for fuchsia_sync::RawMutex in raw_userspace_mutex.rs.
- Rewrite KMutex to be generic over RawLock and require PinInit for safe
  dynamic initialization and stack-pinned locking.
- Rewrite the #[guarded] macro to generate LockClass registrations,
  pinned guard structures, and safe projected accessors.
- Update userspace unit tests to use pin_init! and stack_pin_init!.

Test: ksync-tests builds successfully with the new pinned architecture.
Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1630128
Original-Original-Revision: 619529feb1bd6fd8fe03307b13f8bc2218452e99
GitOrigin-RevId: 2068870f78f4f656469d61d2dbdab6c0afa59473
Change-Id: I12219f01d399523d7903add0e0f47bf20bda1f3e
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1634909
Cr-Commit-Position: refs/heads/main@{#193829}