dev: remove pub/sub architecture

[EvolveArt]

Simplify Indexer Service Architecture

Problem

Current architecture is over-engineered for the use case, using SQS queues for rare operations like creating/starting/stopping indexers. This adds unnecessary complexity and infrastructure requirements.

Proposed Changes

• Remove all SQS-related code and configurations
• Remove the entire consumer pattern
• Create a new IndexerService struct to handle operations directly:
• Update API Handlers
• Streamline error types for direct operations
• Remove SQS-related test setup
• Simplify test cases to focus on direct service operations
• Update integration tests to remove queue checks
• Infrastructure Updates
• Remove LocalStack SQS configuration
• Update deployment configurations to remove SQS permissions/setup
• Simplify local development setup

Benefits

• Simpler codebase
• Easier to understand and maintain
• Reduced infrastructure requirements
• Simpler local development
• More direct error handling
• Fewer dependencies

Migration Steps

1. Create new service structure
2. Update tests
3. Remove old code once new implementation is verified
4. Update documentation

Breaking Changes

• API behavior will change from async to sync for some operations
• Deployment requirements will change (no SQS needed)