Convert project to ES modules (align tooling with the service repo)

.editorconfig

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+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[{*.yml,*.yaml}]
+indent_style = space

.npmrc

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+engine-strict=true

.prettierignore

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+# Ignore artifacts:
+dist
+coverage
+
+# Lock file (machine-generated, not hand-formatted):
+package-lock.json
+
+# Python scripts and generated data live outside the TS project:
+standalone/
+
+# The pre-existing .github configs and README likewise predate the shared
+# prettier config; reformatting them here is ESM-unrelated churn (YAML quote
+# style, Markdown spacing). Defer to the same separate follow-up.
+.github/
+README.md

.prettierrc

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+{
+  "singleQuote": true,
+  "printWidth": 120
+}

eslint.config.mjs

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+import { defineConfig } from 'eslint/config';
+import js from '@eslint/js';
+import love from 'eslint-config-love';
+import pino from 'eslint-plugin-pino';
+import tseslint from 'typescript-eslint';
+import prettier from 'eslint-config-prettier';
+
+import sortExports from 'eslint-plugin-sort-exports';
+import globals from 'globals';
+
+export default defineConfig([
+  js.configs.recommended,
+  tseslint.configs.eslintRecommended,
+  tseslint.configs.recommendedTypeChecked,
+  tseslint.configs.strict,
+  {
+    ...love,
+    languageOptions: {
+      parserOptions: {
+        project: './tsconfig.dev.json',
+      },
+    },
+  },
+  {
+    plugins: {
+      pino: pino,
+    },
+    rules: {
+      'pino/correct-args-position': 'error',
+    },
+  },
+  prettier,
+  {
+    plugins: {
+      'sort-exports': sortExports,
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.node,
+        ...globals.jest,
+      },
+
+      parserOptions: {
+        project: './tsconfig.dev.json',
+      },
+    },
+
+    rules: {
+      '@typescript-eslint/no-magic-numbers': [
+        'error',
+        {
+          detectObjects: false,
+          ignoreEnums: true,
+          // 0, 1, and -1 are conventionally not considered "magic" numbers.
+          ignore: [0, 1, -1],
+        },
+      ],
+
+      // Unlike some code bases we explicitly do not want to use default exports.
+      'import/prefer-default-export': 'off',
+      'import/no-default-export': 'error',
+
+      'import/order': [
+        'error',
+        {
+          groups: ['builtin', 'external', 'internal', 'parent', 'sibling', 'index', 'object', 'type'],
+          'newlines-between': 'never',
+        },
+      ],
+
+      '@typescript-eslint/no-unused-vars': [
+        'error',
+        {
+          caughtErrors: 'none',
+        },
+      ],
+    },
+    settings: {
+      'import/resolver': {
+        typescript: {
+          alwaysTryTypes: true,
+          project: './tsconfig.dev.json',
+        },
+        node: true,
+      },
+    },
+  },
+  {
+    files: ['**/index.ts'],
+
+    rules: {
+      'sort-exports/sort-exports': [
+        'error',
+        {
+          sortDir: 'asc',
+          ignoreCase: true,
+        },
+      ],
+      // Indexes shouldn't care about the nature of the exports they are collating
+      '@typescript-eslint/consistent-type-exports': 'off',
+    },
+  },
+  {
+    files: ['**/*test.ts'],
+
+    rules: {
+      // Forcing return type definitions in our ad-hoc test functions is not worth
+      // the added effort / verbosity.
+      '@typescript-eslint/explicit-function-return-type': 'off',
+
+      // Tests use hard coded numbers in lots of places, and that's OK for now.
+      '@typescript-eslint/no-magic-numbers': 'off',
+
+      // Jest hoists mock statements, so sometimes we need to define mock functions
+      // that are used in mocks BEFORE the import block.  There may be a better
+      // approach to this, but for now it is how we do it and so the rule must go.
+      'import/first': 'off',
+
+      // The way we organize tests our test files can be very long since we're comprehensive.
+      // We could refactor, potentially, but even then I imagine that a line limit is not
+      // going to be useful in this context.
+      'max-lines': 'off',
+
+      // Tests are already 2-3 levels deep in nested callbacks, so we update this rule to 5 instead of 3.
+      'max-nested-callbacks': ['error', 5],
+    },
+  },
+]);

jest.config.cjs

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+module.exports = {
+  transform: {
+    '^.+[.]tsx?$': [
+      'ts-jest',
+      {
+        // The project is `"type": "module"`, so jest runs in ESM mode
+        // (see the `test` script's `--experimental-vm-modules` flag).
+        // ts-jest emits ESM and keeps `module: nodenext` from tsconfig.dev.json,
+        // which correctly resolves `exports` subpaths such as `csv-parse/sync`.
+        // Type-checking of tests is also covered by `npm run lint:tsc`.
+        // Authored by GLM-5.2.
+        tsconfig: 'tsconfig.dev.json',
+        useESM: true,
+      },
+    ],
+  },
+  extensionsToTreatAsEsm: ['.ts'],
+  testEnvironment: 'node',
+  moduleFileExtensions: ['ts', 'js'],
+  moduleNameMapper: {
+    '^([.]{1,2}/.*)[.]js$': '$1',
+  },
+  testMatch: ['**/*.unit.test.ts'],
+  passWithNoTests: true,
+  silent: true,
+};