Hide deprecated schema elements from query validation when generateDeprecated is false

[velo]

Problem

generateDeprecated = false only stopped the generator from emitting deprecated fields and enum constants. Queries were still validated against the full schema, so selecting a deprecated field compiled fine and the field was silently dropped from the generated record.

Change

When the effective generateDeprecated (class-level, or method-level Toggle override) is false, QueryValidator walks each query with graphql-java's QueryTraverser after normal validation and reports every deprecated element it uses: fields, arguments, input fields, enum values, including enum values in variable defaults. The error names the element and its @deprecated reason, e.g. Field 'email' is deprecated (use emails instead) and generateDeprecated is false.

An earlier revision stripped deprecated elements from a copy of the schema. That made graphql-java reject valid schemas (enum or input defaults that use a deprecated value, types whose fields are all deprecated, interface fields deprecated in an implementation) for every interface, so it was replaced.

Also removes the deprecated-field filter in TypeGenerator.buildResultType, which can no longer run, and documents the setting in graphql-apt/README.md.

Behaviour change

Interfaces that select deprecated fields with generateDeprecated = false used to compile (dropping the field) and now fail with a GraphQL validation error.

Tests

• Parameterized cases for a deprecated field (literal and variable argument), argument, enum literal, enum variable default, and input-object field, each asserting its message, with the toggle set at class level and at method level; the same queries compile when enabled
• deprecated-edge-schema.graphql fixture with the schema shapes that broke the stripping approach, compiled with the flag on and off
• Removed assertions that could no longer fail