Hierarchical Indexing with Closure Table

Description

To ensure high-performance hierarchical queries (e.g., finding all files in a directory subtree), a Closure Table pattern will be implemented in the database. This pre-calculates all ancestor-descendant relationships.

Implementation Notes

• The schema will be defined in src/infrastructure/database/entities/entry_closure.rs.
• Query helpers for traversing the hierarchy (e.g., get_descendants, get_ancestors) will be implemented in src/operations/indexing/hierarchy.rs.
• The indexing process in src/operations/indexing/phases/processing.rs correctly populates the closure table upon entry creation.

Acceptance Criteria

• The database contains an entry_closure table.
• Creating a new file entry correctly populates its ancestor relationships.
• Subtree and ancestor queries are efficient and do not require recursive SQL.