feat(amp-data-store): introduce crate with unified store interface

[LNSD]

Consolidate data storage and caching into a single abstraction to simplify the architecture and eliminate the distinction between cached/uncached stores.

• Unified DataStore combines storage and cache in a single type
• Integrated parquet metadata cache with memory-aware eviction
• Centralized physical table operations and file naming
• Single store interface across all services and modules

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Note

Introduces a unified data access layer and refactors the codebase to use it.

• Add new amp-data-store crate providing DataStore (object store + metadata DB) with integrated parquet footer cache (memory-weighted eviction via foyer)
• Move physical-table utilities (PhyTableUrl, PhyTablePath, PhyTableRevisionPath) and FileName into amp-data-store; update error types and uses
• Remove common::store (including CachedStore); replace with DataStore in common catalog/metadata/reader/query_context and related APIs
• Refactor services (server, controller, worker, admin-api), CLI (ampd), dump, datasets-derived, and tests to depend on and construct DataStore (passing config.parquet.cache_size_mb)
• Config/query env: drop parquet_cache_size_mb from QueryEnv/server config and Config::make_query_env; caching handled by DataStore::new
• Minor API/log tweaks: StreamingQueryHandle::as_stream → into_stream, replace debug! with tracing::debug! in some paths

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