feat(query/apiv3): implement GetDependencies gRPC handler

[Sapthagiri777]

Implements jaegertracing/jaeger-idl#45
Fixes #7595

Which problem is this PR solving?

Implements API v3 GetDependencies RPC defined in jaegertracing/jaeger-idl#45 to enable service dependency graph queries. Completes #7595

Description of the changes

• Added GetDependencies gRPC handler to cmd/jaeger/internal/extension/jaegerquery/internal/apiv3/grpc_handler.go
• Delegates to existing traceQueryManager.GetDependencies() storage backend
• Converts model.Dependencies → api_v3.DependenciesResponse (parent/child/call_count)
• Uses correct v3 proto types: api_v3.GetDependenciesRequest/Response
• Formatted with make fmt, passes make lint

How was this change tested?

• make fmt ✅
• make lint ✅
• Ready for make test in CI
• Follows pattern of existing GetOperations handler

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality (minimal handler - add in follow-up)
• I have run lint and test steps successfully
  • for jaeger: make lint ✅