chore: migrate tests from tests-ui/ to colocate with source files (#7811)

## Summary

Migrates all unit tests from `tests-ui/` to colocate with their source
files in `src/`, improving discoverability and maintainability.

## Changes

- **What**: Relocated all unit tests to be adjacent to the code they
test, following the `<source>.test.ts` naming convention
- **Config**: Updated `vitest.config.ts` to remove `tests-ui` include
pattern and `@tests-ui` alias
- **Docs**: Moved testing documentation to `docs/testing/` with updated
paths and patterns

## Review Focus

- Migration patterns documented in
`temp/plans/migrate-tests-ui-to-src.md`
- Tests use `@/` path aliases instead of relative imports
- Shared fixtures placed in `__fixtures__/` directories

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7811-chore-migrate-tests-from-tests-ui-to-colocate-with-source-files-2da6d73d36508147a4cce85365dee614)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: GitHub Action <action@github.com>

src/services/nodeSearchService.test.ts

@@ -0,0 +1,77 @@
+import { describe, expect, it } from 'vitest'
+
+import type { ComfyNodeDef } from '@/schemas/nodeDefSchema'
+import { NodeSearchService } from '@/services/nodeSearchService'
+import { ComfyNodeDefImpl } from '@/stores/nodeDefStore'
+
+const EXAMPLE_NODE_DEFS: ComfyNodeDefImpl[] = (
+  [
+    {
+      input: {
+        required: {
+          ckpt_name: [['model1.safetensors', 'model2.ckpt'], {}]
+        }
+      },
+      output: ['MODEL', 'CLIP', 'VAE'],
+      output_is_list: [false, false, false],
+      output_name: ['MODEL', 'CLIP', 'VAE'],
+      name: 'CheckpointLoaderSimple',
+      display_name: 'Load Checkpoint',
+      description: '',
+      python_module: 'nodes',
+      category: 'loaders',
+      output_node: false
+    },
+    {
+      input: {
+        required: {
+          samples: ['LATENT'],
+          batch_index: [
+            'INT',
+            {
+              default: 0,
+              min: 0,
+              max: 63
+            }
+          ],
+          length: [
+            'INT',
+            {
+              default: 1,
+              min: 1,
+              max: 64
+            }
+          ]
+        }
+      },
+      output: ['LATENT'],
+      output_is_list: [false],
+      output_name: ['LATENT'],
+      name: 'LatentFromBatch',
+      display_name: 'Latent From Batch',
+      description: '',
+      python_module: 'nodes',
+      category: 'latent/batch',
+      output_node: false
+    }
+  ] as ComfyNodeDef[]
+).map((nodeDef: ComfyNodeDef) => {
+  const def = new ComfyNodeDefImpl(nodeDef)
+  def['postProcessSearchScores'] = (s) => s
+  return def
+})
+
+describe('nodeSearchService', () => {
+  it('searches with input filter', () => {
+    const service = new NodeSearchService(EXAMPLE_NODE_DEFS)
+    const inputFilter = service.inputTypeFilter
+    expect(
+      service.searchNode('L', [{ filterDef: inputFilter, value: 'LATENT' }])
+    ).toHaveLength(1)
+    // Wildcard should match all.
+    expect(
+      service.searchNode('L', [{ filterDef: inputFilter, value: '*' }])
+    ).toHaveLength(2)
+    expect(service.searchNode('L')).toHaveLength(2)
+  })
+})