[core] Add access context for blob view fallback

[leaves12138]

Purpose

Blob view resolution may need to access an upstream blob table while users are querying a downstream blob-view table. Permission systems need to distinguish this fallback access from a direct upstream table query.

Changes

• Add TableAccessContext to describe table access origins.
• Add context-aware Catalog#getTable and Catalog#authTableQuery default overloads.
• Carry table access context through CatalogEnvironment so scans can pass the same context to query auth.
• Pass BLOB_VIEW_FALLBACK context from DataEvolutionTableRead / BlobViewLookup when resolving upstream blob descriptors and URI readers.
• Add a focused test to verify access context reaches query auth.

Tests

• mvn -pl paimon-core -DskipITs -Dspotless.check.skip=true -Dcheckstyle.skip=true -Dtest=CatalogAccessContextTest test
• mvn -pl paimon-core -DskipITs -DskipTests -Dspotless.check.skip=true -Dcheckstyle.skip=true test-compile

[JingsongLi]

LGTM. Clean design for distinguishing blob-view fallback access from direct table queries. This is important for permission systems that need to know the access origin.

The approach is well-structured:

• TableAccessContext is a simple, serializable value type with factory methods
• Default method overloads on Catalog interface maintain backwards compatibility
• CatalogEnvironment carries the context through to scans and blob resolution
• DelegateCatalog and PrivilegedCatalog properly propagate the new overloads

One minor thought: the TableAccessContext.direct() factory creates a new instance each call. Since it's immutable and always the same, you could cache it as a static constant to avoid allocation in hot paths (e.g., private static final TableAccessContext DIRECT = new TableAccessContext(AccessType.DIRECT, null)). Not a blocker.

+1

[JingsongLi]

This PR needs more discussion about REST integration.

[leaves12138]

I re-checked the latest state. This still needs the REST integration discussion from the existing requested-changes review before I would consider it ready.