Remove GraphQL API and standardize on REST API only

[devin-ai-integration]

Summary

This PR removes GraphQL support from the application, standardizing on the REST API only. The changes include:

• Deleted the entire io.spring.graphql package (12 Java files including datafetchers, mutations, and exception handlers)
• Removed the GraphQL schema file (schema.graphqls)
• Removed Netflix DGS codegen plugin and GraphQL dependency from build.gradle
• Removed /graphql and /graphiql endpoint permissions from security configuration
• Updated README to remove GraphQL documentation

The shared business logic layer (io.spring.application, io.spring.core, io.spring.infrastructure) and REST controllers (io.spring.api) remain unchanged.

Review & Testing Checklist for Human

• Verify REST endpoints work by running the app and testing: curl http://localhost:8080/tags and curl http://localhost:8080/articles
• Consider removing the orphaned graphql-schema.png image file that's no longer referenced in README

Notes

All 68 existing tests pass. The compile and test steps completed successfully locally.

Link to Devin run: https://app.devin.ai/sessions/68f99d79a6bf48d295c968f2fe8a3308
Requested by: @SachetCognition

[devin-ai-integration]

Original prompt from sachet.agarwal

# Task: Remove GraphQL API and Standardize on REST API Only

## Context
This Spring Boot RealWorld application currently supports both REST and GraphQL APIs. Both APIs share the same business logic layer (application services like `UserService`, `ArticleCommandService`, `ArticleQueryService`, etc.), with GraphQL acting as an additional adapter layer. We want to remove GraphQL and standardize on REST only, without losing any functionality.

## Files and Components to Remove

### 1. Remove GraphQL Package
Delete the entire GraphQL package directory:
- `src/main/java/io/spring/graphql/` (entire directory and all files within)

### 2. Remove GraphQL Schema
Delete the GraphQL schema file:
- `src/main/resources/schema/schema.graphqls`

### 3. Update Build Configuration (`build.gradle`)
Remove the following dependency:
- Line with `implementation("com.netflix.graphql.dgs:graphql-dgs-spring-boot-starter:4.9.21")` or similar DGS starter dependency

Remove the DGS codegen plugin configuration if present.

### 4. Update Security Configuration
In `src/main/java/io/spring/api/security/WebSecurityConfig.java`:
- Remove `/graphql` from the list of public endpoints
- Remove `/graphiql` from the list of public endpoints

These endpoints are currently configured as public in the security configuration.

### 5. Update Documentation
In `README.md`:
- Remove all references to GraphQL API
- Remove mentions of the dual API architecture
- Update the technology stack section to remove Netflix DGS Framework

## Important Notes
- **Do NOT modify** any files in the `io.spring.application` package - these contain the shared business logic
- **Do NOT modify** any files in the `io.spring.api` package - these are the REST controllers that will remain
- **Do NOT modify** any files in the `io.spring.core` or `io.spring.infrastructure` packages
- All REST API endpoints remain unchanged and functional

## Verification Steps
After making the changes:
1. Run `./gradlew build` to ensure the project compi... (559 chars truncated...)

[devin-ai-integration]

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[SachetCognition]

Can you also document the architectural changes into a word document

[devin-ai-integration]

I've created a Word document documenting the architectural changes. The document covers:

• Previous architecture (dual REST + GraphQL APIs)
• All GraphQL components that were removed
• Changes made to build configuration and security
• New architecture (REST API only)
• Benefits of the change
• Unchanged components
• Verification steps performed

I'll share the document with you directly.