Which issue does this PR close?

• Closes feat: configure DataFusion's built-in CacheManager from Java #74 .

Rationale for this change

DataFusion's RuntimeEnv accepts a CacheManagerConfig with three independent caches: the file-embedded metadata cache (parquet footers / page metadata), the list-files cache (object-store LIST results), and the file-statistics cache (per-file row counts and column stats used by the planner). The Rust API is RuntimeEnvBuilder::with_cache_manager(CacheManagerConfig). The Java binding has no surface for any of it — every SessionContext ends up with the no-op upstream defaults today, so a parquet workload reading the same footer thousands of times across queries goes back to the object store every single time, and statistics-driven planners can't persist their stats across queries.

This PR adds a typed cacheManager(CacheManagerOptions) setter on SessionContextBuilder that exposes the three caches independently:

SessionContext ctx = SessionContext.builder()
    .cacheManager(CacheManagerOptions.builder()
        .fileMetadataCache(64L << 20)                       // 64 MiB cap
        .listFilesCache(8L << 20, Duration.ofMinutes(5))    // 8 MiB cap, 5min TTL
        .fileStatisticsCache(true)
        .build())
    .build();

Semantics, all matching upstream (datafusion).

Three independent toggles, all matching upstream:

What changes are included in this PR?

• Proto: proto/cache_manager_options.proto.
• Java API: org.apache.datafusion.CacheManagerOptions
• Native: native/src/cache_manager.rs
• Build wiring: proto/cache_manager_options.proto

Are these changes tested?

Yes, 18 new tests cross CacheManagerOptionsTest and SessionContextCacheManagerTest.

Are there any user-facing changes?

Yes, but additive only — no breaking changes:

• New public class org.apache.datafusion.CacheManagerOptions with a static builder() and three setters.
• New SessionContextBuilder.cacheManager(CacheManagerOptions) setter.

No behavior change for callers that do not invoke the new setter — the cache_manager field is absent on the wire and the native side leaves upstream's RuntimeEnvBuilder defaults in place.