feat(wave3): add @mosaic/quality-rails — TypeScript code quality scaffolder

- Project detection: detectProjectKind (node/python/rust/unknown)
- Scaffolder: writes ESLint/Biome/pre-commit configs based on profile
- Embedded templates for strict/standard/minimal profiles
- CLI: quality-rails init | check | doctor
- Depends on @mosaic/types workspace:*

packages/quality-rails/tests/detect.test.ts

@@ -0,0 +1,40 @@
+import { mkdtemp, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { describe, expect, it } from 'vitest';
+
+import { detectProjectKind } from '../src/detect.js';
+
+async function withTempDir(run: (directory: string) => Promise<void>): Promise<void> {
+  const directory = await mkdtemp(join(tmpdir(), 'quality-rails-detect-'));
+  try {
+    await run(directory);
+  } finally {
+    await rm(directory, { recursive: true, force: true });
+  }
+}
+
+describe('detectProjectKind', () => {
+  it('returns node when package.json exists', async () => {
+    await withTempDir(async (directory) => {
+      await writeFile(join(directory, 'package.json'), '{"name":"fixture"}\n', 'utf8');
+
+      await expect(detectProjectKind(directory)).resolves.toBe('node');
+    });
+  });
+
+  it('returns python when pyproject.toml exists and package.json does not', async () => {
+    await withTempDir(async (directory) => {
+      await writeFile(join(directory, 'pyproject.toml'), '[project]\nname = "fixture"\n', 'utf8');
+
+      await expect(detectProjectKind(directory)).resolves.toBe('python');
+    });
+  });
+
+  it('returns unknown when no known project files exist', async () => {
+    await withTempDir(async (directory) => {
+      await expect(detectProjectKind(directory)).resolves.toBe('unknown');
+    });
+  });
+});

packages/quality-rails/tests/scaffolder.test.ts

@@ -0,0 +1,57 @@
+import { mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+import { describe, expect, it } from 'vitest';
+
+import { scaffoldQualityRails } from '../src/scaffolder.js';
+import type { RailsConfig } from '../src/types.js';
+
+async function withTempDir(run: (directory: string) => Promise<void>): Promise<void> {
+  const directory = await mkdtemp(join(tmpdir(), 'quality-rails-scaffold-'));
+  try {
+    await run(directory);
+  } finally {
+    await rm(directory, { recursive: true, force: true });
+  }
+}
+
+describe('scaffoldQualityRails', () => {
+  it('writes expected node quality rails files', async () => {
+    await withTempDir(async (directory) => {
+      await writeFile(join(directory, 'package.json'), '{"name":"fixture"}\n', 'utf8');
+
+      const previous = process.env.MOSAIC_QUALITY_RAILS_SKIP_INSTALL;
+      process.env.MOSAIC_QUALITY_RAILS_SKIP_INSTALL = '1';
+
+      const config: RailsConfig = {
+        projectPath: directory,
+        kind: 'node',
+        profile: 'strict',
+        linters: ['eslint', 'biome'],
+        formatters: ['prettier'],
+        hooks: true,
+      };
+
+      const result = await scaffoldQualityRails(config);
+
+      process.env.MOSAIC_QUALITY_RAILS_SKIP_INSTALL = previous;
+
+      await expect(readFile(join(directory, '.eslintrc'), 'utf8')).resolves.toContain('parser');
+      await expect(readFile(join(directory, 'biome.json'), 'utf8')).resolves.toContain('"formatter"');
+      await expect(readFile(join(directory, '.githooks', 'pre-commit'), 'utf8')).resolves.toContain('pnpm lint');
+      await expect(readFile(join(directory, 'PR-CHECKLIST.md'), 'utf8')).resolves.toContain('Code Review Checklist');
+
+      expect(result.filesWritten).toEqual(
+        expect.arrayContaining([
+          '.eslintrc',
+          'biome.json',
+          '.githooks/pre-commit',
+          'PR-CHECKLIST.md',
+        ]),
+      );
+      expect(result.commandsToRun).toContain('git config core.hooksPath .githooks');
+      expect(result.warnings).toHaveLength(0);
+    });
+  });
+});