Optimize reconcileMetadata: eliminate N+1 DB queries in loops

[VGSML]

Problem

reconcileMetadata in pkg/catalog/db/reconcile.go has multiple N+1 query patterns where individual DB queries are executed inside loops:

1. collectFieldModuleCatalogs (line ~130): When a module is not yet in moduleMap, it does a per-module SELECT query_root, mutation_root, function_root, mut_function_root FROM _schema_modules WHERE name = $1 inside a loop. If there are M modules, this is M extra queries.

2. Module upserts (line ~153): Each module record is inserted/updated with an individual INSERT ... ON CONFLICT query inside a loop.

3. Dependency inserts (line ~183): Each dependency catalog is inserted with an individual INSERT ... ON CONFLICT inside a loop.

4. Data object inserts (line ~199): Each data object is inserted individually inside a loop.

5. Reverse dependency inserts (line ~215): Same pattern.

Proposed fix

• Load _schema_modules table once into a map at the start, instead of querying per-module in the loop.
• Batch all INSERT operations using multi-row INSERT statements (similar to how batchInsertModuleTypeCatalogs already works).
• Consider combining related queries into fewer roundtrips.

Context

This was noticed during work on module catalog-agnostic types. The current code works correctly but is inefficient for catalogs with many modules/dependencies/data objects.