fix(client): lint:layers holds src/types.ts to the rules of types

A file's layer was the first path segment under src/, so src/types.ts,
the shared types module every layer imports as '../types', got the
layer "types.ts" and no rule at all, while the imports into it already
resolved to "types". It could import a component or a page unnoticed.
A file directly in src/ is now the layer of its name without the
extension, for the importer and the import alike. No file changes its
count: types.ts imports only @trek/shared today.

client/tests/unit/scripts/layer-lint.test.ts

@@ -1,7 +1,7 @@
 import { readFileSync } from 'node:fs';
 import { join } from 'node:path';
 import { afterEach, describe, expect, it } from 'vitest';
-import { importsOf, layerOf } from '../../../scripts/lib/imports.mjs';
+import { importsOf, layerOf, layerOfPath } from '../../../scripts/lib/imports.mjs';
 import { check, RULES, violations } from '../../../scripts/lib/layers.mjs';
 import { RatchetError } from '../../../scripts/lib/ratchet.mjs';
 import { ratchetTree, type RatchetTree } from '../../helpers/ratchetFixture';
@@ -57,6 +57,16 @@ describe('scripts/lib/imports', () => {
     expect(layerOf(src, from, 'react')).toBeNull();
     expect(layerOf(src, from, '../../../../shared/src')).toBeNull();
   });
+
+  it('IMPORTS-003: a file directly in src/ is the layer of its name without the extension', () => {
+    expect(layerOfPath('types.ts')).toBe('types');
+    expect(layerOfPath('App.tsx')).toBe('App');
+    expect(layerOfPath('vite-env.d.ts')).toBe('vite-env');
+    expect(layerOfPath('types/tz-lookup.d.ts')).toBe('types');
+    expect(layerOfPath('components/Map/MapView.tsx')).toBe('components');
+    const src = join('/r', 'src');
+    expect(layerOf(src, join(src, 'App.tsx'), './types.ts')).toBe('types');
+  });
 });
 
 describe('lint:layers', () => {
@@ -125,6 +135,15 @@ describe('lint:layers', () => {
     expect(tree.error.join('\n')).toMatch(/src\/vacay\/yearWindow\.ts: 1 import\(s\) against the layering/);
   });
 
+  it('LAYERS-008: src/types.ts is held to the rules of types and imports no view', () => {
+    const files = {
+      'src/types.ts': "import type { Props } from './components/Map/MapView'\nimport type { T } from '@trek/shared'\n",
+    };
+    expect(run({}, files)).toBe(1);
+    expect(tree.error.join('\n')).toMatch(/src\/types\.ts: 1 import\(s\) against the layering/);
+    expect(tree.error.join('\n')).toMatch(/\(types into components\)/);
+  });
+
   it('LAYERS-006: a missing baseline stops the check', () => {
     tree = ratchetTree({ 'src/a.ts': '' });
     expect(() => check({ root: tree.root, baselinePath: tree.path(BASELINE), ...tree.out })).toThrow(RatchetError);