[FEATURE] Implement Lock-Free In-Memory Checkpoint Store using sync/atomic Bitmask Registers

Problem

Stateless userspace reverse proxies throw high scheduling latencies because they allocate data heaps on every multi-tenant runtime failure event [1.5, 1.6]. To handle agent context recovery under 2ms, we cannot rely on heavy mutex locks or continuous garbage collection cycles [1.5].

Proposed Solution

Scaffold an ultra-low-latency in-memory bitmask state cache manager inside internal/storage/cache_manager.go:

1. The Lock-Free Ring Buffer Array: Implement fixed-size pointer registers arrays tracking multi-turn context snapshots using Go's native sync/atomic low-overhead indicators.
2. The Zero-Allocation Serialization Layer: Replace heavy JSON reflection formats with strict byte- snipping memory copy utilities to commit state progress directly to memory maps without heap re-allocations.

Alternatives

Using distributed userspace database caches (like Redis), which was completely rejected due to heavy TCP serialization overheads and thread scheduling blocks.

Use Case

Secures undisputed sub-millisecond tail latency constraints, giving enterprise platform purchasers mathematical proof that FaultPlane isolates failure blast radiuses natively without leaking core compute performance boundaries [1.5, 1.6].

Start by reading internal/storage/cache_manager.go and trace how the repository currently represents and persists runtime state. Define the required checkpoint-store behavior and latency and allocation constraints from the issue before choosing an implementation. Done means the cache manager provides the proposed lock-free, in-memory checkpoint path with zero-allocation serialization and evidence that the stated constraints are met.