ci: restore hosted-run headroom

scripts/lint-shards.ts

@@ -0,0 +1,40 @@
+/** Lint-lane selection for GitHub Actions. */
+
+/** One ESLint target set and whether it owns the cross-file duplication gate. */
+export interface LintSelection {
+  /** Shell-free arguments passed to ESLint before its cache options. */
+  eslintTargets: readonly string[]
+  /** Whether this lane also runs the repository-wide duplication check. */
+  includeDuplication: boolean
+}
+
+/**
+ * Select an exhaustive lint partition without changing the ordinary local lint command.
+ *
+ * @param name Optional stable shard name from `DSH_LINT_SHARD`.
+ * @returns ESLint targets and ownership of the duplication gate.
+ */
+export function selectLintShard(name?: string): LintSelection {
+  switch (name) {
+    case undefined:
+    case '':
+      return { eslintTargets: ['.'], includeDuplication: true }
+    case 'package-sources':
+      return { eslintTargets: ['packages/*/*/src/**/*.ts'], includeDuplication: false }
+    case 'package-tests':
+      return { eslintTargets: ['packages/*/*/tests/**/*.ts'], includeDuplication: false }
+    case 'repository':
+      return {
+        eslintTargets: [
+          '.',
+          '--ignore-pattern',
+          'packages/*/*/src/**',
+          '--ignore-pattern',
+          'packages/*/*/tests/**',
+        ],
+        includeDuplication: true,
+      }
+    default:
+      throw new Error(`run-gates: unknown DSH_LINT_SHARD ${JSON.stringify(name)}.`)
+  }
+}