feat(gsm): add standardised error fields to GSM models and database schema

[ayush22667]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

This PR adds new columns to the GSM (Gateway Status Mapping) table and updates the create/update APIs to include these new fields for better error categorization and user guidance.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

closes #10599

How did you test it?

Create Request:

curl --location 'http://localhost:8080/gsm' \
--header 'Content-Type: application/json' \
--header 'api-key: test_admin' \
--data '{
  "connector": "stripe",
  "flow": "Payment",
  "sub_flow": "Authoriz",
  "code": "card_declined",
  "message": "Your card was declined.",
  "status": "Failure",
  "router_error": "CARD_DECLINED",
  "decision": "retry",
  "step_up_possible": true,
  "unified_code": "IR_01",
  "unified_message": "Card declined by issuer",
  "error_category": "processor_downtime",
  "clear_pan_possible": false,
  "feature": "retry",
  "feature_data": {
    "retry": {
      "step_up_possible": true,
      "clear_pan_possible": false,
      "alternate_network_possible": true,
      "decision": "retry"
    }
  },
  "standardised_code": "PM_INSUFFICIENT_FUNDS",
  "description": "The card was declined due to insufficient funds in the account.",
  "user_guidance_message": "Your payment was declined due to insufficient funds. Please use a different card or add funds to your account."
}'

Response:

{
    "connector": "stripe",
    "flow": "Payment",
    "sub_flow": "Authoriz",
    "code": "card_declined",
    "message": "Your card was declined.",
    "status": "Failure",
    "router_error": "CARD_DECLINED",
    "decision": "retry",
    "step_up_possible": true,
    "unified_code": "IR_01",
    "unified_message": "Card declined by issuer",
    "error_category": "processor_downtime",
    "clear_pan_possible": false,
    "feature": "retry",
    "feature_data": {
        "retry": {
            "step_up_possible": true,
            "clear_pan_possible": false,
            "alternate_network_possible": true,
            "decision": "retry"
        }
    },
    "standardised_code": "PM_INSUFFICIENT_FUNDS",
    "description": "The card was declined due to insufficient funds in the account.",
    "user_guidance_message": "Your payment was declined due to insufficient funds. Please use a different card or add funds to your account."
}

Get Request :

curl --location 'http://localhost:8080/gsm/get' \
--header 'Content-Type: application/json' \
--header 'api-key: test_admin' \
--data '
{
  "connector": "stripe",
  "flow": "Payment",
  "sub_flow": "Authoriz",
  "code": "card_declined",
  "message": "Your card was declined."
}
'

Response:

{
    "connector": "stripe",
    "flow": "Payment",
    "sub_flow": "Authoriz",
    "code": "card_declined",
    "message": "Your card was declined.",
    "status": "Failure",
    "router_error": "CARD_DECLINED",
    "decision": "retry",
    "step_up_possible": true,
    "unified_code": "IR_01",
    "unified_message": "Card declined by issuer",
    "error_category": "processor_downtime",
    "clear_pan_possible": false,
    "feature": "retry",
    "feature_data": {
        "retry": {
            "step_up_possible": true,
            "clear_pan_possible": false,
            "alternate_network_possible": true,
            "decision": "retry"
        }
    },
    "standardised_code": "PM_INSUFFICIENT_FUNDS",
    "description": " was declined due to insufficient funds in the account.",
    "user_guidance_message": "Your payment was declined due to insufficient funds. Please use a different card or add funds to your account."
}

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
api-reference/v1/openapi_spec_v1.json	0% smaller
api-reference/v2/openapi_spec_v2.json	0% smaller
crates/api_models/src/gsm.rs	0% smaller
crates/common_enums/src/enums.rs	0% smaller
crates/diesel_models/src/gsm.rs	0% smaller
crates/diesel_models/src/schema.rs	0% smaller
crates/diesel_models/src/schema_v2.rs	0% smaller
crates/hyperswitch_domain_models/src/gsm.rs	0% smaller
crates/openapi/src/openapi.rs	0% smaller
crates/openapi/src/openapi_v2.rs	0% smaller
crates/router/src/core/gsm.rs	0% smaller
crates/router/src/types/transformers.rs	0% smaller
migrations/2025-12-10-114754_add_standardised_fields_to_gsm/down.sql	Unsupported file format
migrations/2025-12-10-114754_add_standardised_fields_to_gsm/up.sql	Unsupported file format

[codecov]

Codecov Report

❌ Patch coverage is 0% with 21 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@2543a81). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
crates/hyperswitch_domain_models/src/gsm.rs	0.00%	9 Missing ⚠️
crates/diesel_models/src/gsm.rs	0.00%	6 Missing ⚠️
crates/router/src/types/transformers.rs	0.00%	6 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10600   +/-   ##
=======================================
  Coverage        ?    6.44%           
=======================================
  Files           ?     1254           
  Lines           ?   313662           
  Branches        ?        0           
=======================================
  Hits            ?    20209           
  Misses          ?   293453           
  Partials        ?        0           

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[ShankarSinghC]

Can we improve the doc comments for these fields ?