lambda-layer-ssm-parameters: Update runtime to nodejs22.x

[kakakakakku]

Issue #, if available:
N/A

Description of changes:
Hi😀 Thanks for the useful patterns!

To prevent future deployment issues, I updated the deprecated Lambda Node.js runtime nodejs16.x to nodejs22.x.
See https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html

Error

Some error occurs.

2025-10-04T10:13:12.893Z	undefined	ERROR	Uncaught Exception 	
{
    "errorType": "Error",
    "errorMessage": "Cannot find module '/opt/nodejs/config.mjs' imported from /var/task/app.mjs",
    "code": "ERR_MODULE_NOT_FOUND",
    "url": "file:///opt/nodejs/config.mjs",
    "stack": [
        "Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/opt/nodejs/config.mjs' imported from /var/task/app.mjs",
        "    at finalizeResolution (node:internal/modules/esm/resolve:280:11)",
        "    at moduleResolve (node:internal/modules/esm/resolve:865:10)",
        "    at moduleResolveWithNodePath (node:internal/modules/esm/resolve:989:14)",
        "    at defaultResolve (node:internal/modules/esm/resolve:1032:79)",
        "    at ModuleLoader.defaultResolve (node:internal/modules/esm/loader:783:12)",
        "    at #cachedDefaultResolve (node:internal/modules/esm/loader:707:25)",
        "    at ModuleLoader.resolve (node:internal/modules/esm/loader:690:38)",
        "    at ModuleLoader.getModuleJobForImport (node:internal/modules/esm/loader:307:38)",
        "    at ModuleJob._link (node:internal/modules/esm/module_job:183:49)"
    ]
}

So I update src structure.

• https://docs.aws.amazon.com/lambda/latest/dg/packaging-layers.html

lambda-layer-ssm-parameters/layer/src/config.mjs‎ renamed to ‎lambda-layer-ssm-parameters/layer/src/nodejs/config.mjs‎
lambda-layer-ssm-parameters/layer/src/package.json‎ renamed to ‎lambda-layer-ssm-parameters/layer/src/nodejs/package.json‎

Check

sam deploy completed successfully and works good.

$ curl -s https://p6sqx5pqckmcjkeg2mvoae3xhy0nmdhg.lambda-url.ap-northeast-1.on.aws/ | jq .
{
  "$metadata": {
    "httpStatusCode": 200,
    "requestId": "7b22348e-901f-46c5-a687-eac918da84b7",
    "attempts": 1,
    "totalRetryDelay": 0
  },
  "Parameters": [
    {
      "ARN": "arn:aws:ssm:ap-northeast-1:000000000000:parameter/Config/Parameter1Name",
      "DataType": "text",
      "LastModifiedDate": "2025-10-04T10:10:20.077Z",
      "Name": "/Config/Parameter1Name",
      "Type": "String",
      "Value": "Value1",
      "Version": 1
    },
    {
      "ARN": "arn:aws:ssm:ap-northeast-1:000000000000:parameter/Config/Parameter2Name",
      "DataType": "text",
      "LastModifiedDate": "2025-10-04T10:10:20.115Z",
      "Name": "/Config/Parameter2Name",
      "Type": "String",
      "Value": "{\n  \"key1\": \"value1\",\n  \"key2\": \"value2\"\n}",
      "Version": 1
    }
  ]
}

Thank you😀

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