GraphQL select projection drops sub-selections for aliased relationships and relationships nested in arrays/blocks

Describe the Bug

When the GraphQL API resolves a relationship/upload field, it derives a select
projection from the GraphQL query (resolveSelect in @payloadcms/graphql). That
projection is silently dropped — and the relationship is fetched without its
sub-selection — in three cases:

1. Aliased relationship fields. resolveSelect looks the field up in the schema
   with path.key, which is the response key (the alias) rather than the real field
   name. An aliased relationship (myAlias: myRelation { ... }) is not found in the
   field map, so its sub-selection is not projected.

2. Relationships nested inside arrays / blocks / uploads. formattedNameResolver
   only attaches extensions.field when the GraphQL name differs from the data name.
   Sub-fields whose name is already camelCase (typical inside arrays/blocks) get no
   extensions.field, so resolveSelect cannot map them back to a data field and the
   traversal breaks.

3. Relationships inside a block (union). buildSelectTree nests a block's
   sub-selection under the block slug, but resolveSelect's traversal never pushes the
   block slug onto its lookup path, so the paths do not line up.

On the SQL adapters (postgres/sqlite) the result is that the nested relationship comes
back id-only (or null), losing the queried sub-fields.

Link to reproduction

Added as an integration test in test/collections-graphql (see linked PR).

Which area(s) are affected?

area: core, GraphQL

Environment

• Payload version: 3.x (reproduced on latest 3.88.0)
• Adapter: @payloadcms/db-postgres (and @payloadcms/db-sqlite)

Start with resolveSelect in @payloadcms/graphql, then trace formattedNameResolver and buildSelectTree to compare GraphQL response keys with data-field paths. Use the integration tests in test/collections-graphql as the reproduction point. Done means aliased relationships and relationships in arrays, blocks, uploads, and block unions retain their queried sub-selections on the SQL adapters.