mos-cache 0.0.1

# MOS-CACHE KNOWLEDGE BASE

## OVERVIEW

`mos-cache` is a tiny cache trait plus in-memory byte map. Persistent incremental builds are not
implemented yet.

## WHERE TO LOOK

| Task             | Location     | Notes                                      |
| ---------------- | ------------ | ------------------------------------------ |
| Cache API        | `src/lib.rs` | `Cache`, `CacheKey`, `InMemoryCache`.      |
| Key source       | `mos-core`   | `CacheKey` wraps current `ContentHash`.    |
| Future direction | `README.md`  | Treat as intent unless code implements it. |

## CURRENT SLICE

- Depends only on `mos-core`.
- `CacheKey` is opaque and currently wraps `ContentHash`.
- `Cache` stores and returns `Vec<u8>` payloads.
- `InMemoryCache` uses a `HashMap` and clones payloads on `get`.
- Serialization, validation, and type meaning of bytes are caller responsibility.

## BOUNDARY RULES

- Keep this crate below parse/eval/layout/PDF/CLI/LSP until real integration exists.
- Cache invalidation/versioning/locking/eviction must be modeled explicitly before use.
- Disk persistence needs a real schema and tests; no ad hoc `.mos-cache/` writes.

## ANTI-PATTERNS

- Do not pretend `CacheKey` is the final manifest dependency key schema.
- Do not add filesystem writes or global cache state casually.
- Do not wire into `mos build` unless implementing the full behavior slice.