feat: add product service resolver

[saurabhhhcodes]

Summary

• add a ProductServiceClient that calls the product-service /products list/create endpoints through the gateway WebClient stack
• expose getProducts and createProduct GraphQL mappings with Product / ProductInput schema types
• add focused resolver and client unit tests for delegation and endpoint wiring

Closes #30

Validation

• git diff --check
• conflict-marker scan across touched gateway source/schema/test files

I could not run ./mvnw test locally because this machine does not have a Java runtime installed (Unable to locate a Java Runtime). The root mvn command is also unavailable in this environment. The PR is limited to gateway resolver/client/schema wiring plus focused unit tests.

NSoC Labels Requested

Please keep/add nsoc26 and level3 if accepted.

[saurabhhhcodes]

Quick review note for issue #30: this PR is clean/mergeable from GitHub’s side and implements the product-service resolver/client path requested in the assigned issue.

Local validation available from this machine:

• git diff --check
• conflict-marker scan across the touched gateway source/schema/test files

I could not run the Maven suite locally because this machine has no Java runtime, so I kept that limitation explicit in the PR body. If the implementation is accepted for NSoC, could you please add the scoring labels from the linked issue (nsoc26, level3) on the PR before merge?

[saurabhhhcodes]

Quick follow-up: this PR is still clean and mergeable from GitHub's side. If there are no remaining changes needed, please review and merge when convenient; I can respond quickly if you want any adjustments.

[saurabhhhcodes]

Quick follow-up on this PR: the product-service resolver branch is still clean and mergeable from GitHub's side, and the scope remains focused to the assigned issue path. If you want any final adjustments before merge, I can turn them around quickly.

[pooranjoyb]

gimme graphql + swagger screenshots of working api

[saurabhhhcodes]

Added the requested working API proof screenshots on the PR branch in commit 85f7990.

Local proof setup used:

• product.service running on localhost:8081
• order.service running on localhost:8080
• graphql.gateway running on localhost:5001
• PostgreSQL product_service on port 5435

Screenshots:

Product Swagger

GraphQL createProduct mutation

GraphQL getProducts query

DB rows showing created products

I also kept an order-service Swagger proof in the branch assets for completeness:

[saurabhhhcodes]

Quick follow-up after your Swagger + GraphQL proof request: the product Swagger, GraphQL create/query screenshots, DB rows, and supporting order Swagger proof are attached above. The PR is still clean/mergeable from GitHub side, so please let me know if anything else is needed before review/merge.

[pooranjoyb]

please resolve the conflicts