feat(lint): adopt @constructive-io/eslint-config flat config

ESLint 9 only reads flat config, so pnpm lint has been failing repo-wide since
the eslint 8 -> 9 bump. Replaces .eslintrc.json with an eslint.config.mjs on
top of the shared package, plus repo-local ignores for codegen output and a few
rule relaxations for idioms this repo relies on.

Author: pyramation

.eslintrc.json

@@ -0,0 +1,48 @@
+import base from '@constructive-io/eslint-config';
+
+export default [
+  ...base,
+  {
+    // several rules this repo turns off still have inline disable comments;
+    // leave them in place rather than have --fix strip them
+    linterOptions: {
+      reportUnusedDisableDirectives: 'off'
+    }
+  },
+  {
+    ignores: [
+      // codegen output, regenerated by `pnpm generate`
+      'sdk/*/src/**',
+      '**/__generated__/**',
+      '**/*.generated.ts',
+      'postgres/pg-ast/src/asts.ts',
+      'postgres/pg-ast/src/wrapped.ts',
+      // legacy fixture build script
+      '__fixtures__/kitchen-sink/**'
+    ]
+  },
+  {
+    rules: {
+      // `declare global { namespace Grafast { ... } }` augmentations
+      '@typescript-eslint/no-namespace': 'off',
+      // `Function` in plugin/callback signatures
+      '@typescript-eslint/no-unsafe-function-type': 'off',
+      // `{}` as a type-level marker (StrictSelect) and placeholder option bags
+      '@typescript-eslint/no-empty-object-type': 'off'
+    }
+  },
+  {
+    // ANSI escapes are matched on purpose
+    files: ['pgpm/logger/**'],
+    rules: {
+      'no-control-regex': 'off'
+    }
+  },
+  {
+    // type-level assertions are expressions by construction
+    files: ['**/*.type-test.ts'],
+    rules: {
+      '@typescript-eslint/no-unused-expressions': 'off'
+    }
+  }
+];

eslint.config.mjs

@@ -25,6 +25,7 @@
     "fixtures:install:force": "node pgpm/cli/dist/index.js install -W --force"
   },
   "devDependencies": {
+    "@constructive-io/eslint-config": "^0.2.0",
     "@jest/test-sequencer": "^30.4.1",
     "@types/jest": "^30.0.0",
     "@types/jest-in-case": "^1.0.9",