feat(ir): add scaffolding for GraphQL SDK generation via Transport.graphql

[cadesark]

Description

Adds the file structure and type stubs for GraphQL SDK generation using "Path B" (GraphQL-Aware approach). Each GraphQL root field becomes a synthetic HttpEndpoint with a new Transport.graphql variant carrying a pre-built query string, typed variables as the request body, and the unwrapped return type as the response.

No implementation logic yet — all functions are stubs with TODO markers describing the algorithm at each point.

Changes Made

Layer 1: IR Type Changes

• New graphql.yml definition file (parallel to proto.yml):
  • GraphqlTransport { query: string, operationType, operationName }
  • GraphqlOperationType enum: QUERY | MUTATION | SUBSCRIPTION
• Added graphql: graphql.GraphqlTransport variant to Transport union in http.yml
• Bumped IR version 67.6.0 → 67.7.0

Layer 2: GraphQL → IR Converter

• GraphQLToIRConverter class — main entry, parallel to ProtobufIRGenerator
• ir-conversion/convertGraphQLTypes.ts — schema objects/enums/unions → IR TypeDeclarations
• ir-conversion/convertRootFieldToEndpoint.ts — root field → HttpEndpoint with Transport.graphql

Layer 5: Query Auto-Generation

• query-generation/generateSelectionQuery.ts — produces full-selection query string per root field
• SelectionSetBuilder class — hybrid depth limiting (cycle detection + max depth 4 cap)

Layer 3: Pipeline Integration

• GraphQLIRGenerator in lazy-fern-workspace/src/graphql/ — calls converter, returns IR for merging
• INTEGRATION_NOTES.md — documents exact OSSWorkspace + SdkChecker changes needed to wire it in

Exports

• Updated packages/cli/api-importers/graphql/src/index.ts to export GraphQLToIRConverter + query utilities

Testing

• This is scaffolding only — no runtime behavior yet
• Implementation will be filled in subsequent PRs
• pnpm ir:generate and generator updates are deferred until stubs are implemented

Link to Devin session: https://app.devin.ai/sessions/d32b64ce79af434b8e931a4fd849e058
Requested by: @cadesark

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