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>

tests-ui/tests/composables/useServerLogs.test.ts

@@ -1,121 +0,0 @@
-import { useEventListener } from '@vueuse/core'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
-import { nextTick } from 'vue'
-
-import { useServerLogs } from '@/composables/useServerLogs'
-import type { LogsWsMessage } from '@/schemas/apiSchema'
-import { api } from '@/scripts/api'
-
-vi.mock('@/scripts/api', () => ({
-  api: {
-    subscribeLogs: vi.fn(),
-    addEventListener: vi.fn(),
-    removeEventListener: vi.fn()
-  }
-}))
-
-vi.mock('@vueuse/core', () => ({
-  useEventListener: vi.fn().mockReturnValue(vi.fn())
-}))
-
-describe('useServerLogs', () => {
-  beforeEach(() => {
-    vi.clearAllMocks()
-  })
-
-  it('should initialize with empty logs array', () => {
-    const { logs } = useServerLogs()
-    expect(logs.value).toEqual([])
-  })
-
-  it('should not subscribe to logs by default', () => {
-    useServerLogs()
-    expect(api.subscribeLogs).not.toHaveBeenCalled()
-  })
-
-  it('should subscribe to logs when immediate is true', () => {
-    useServerLogs({ immediate: true })
-    expect(api.subscribeLogs).toHaveBeenCalledWith(true)
-  })
-
-  it('should start listening when startListening is called', async () => {
-    const { startListening } = useServerLogs()
-
-    await startListening()
-
-    expect(api.subscribeLogs).toHaveBeenCalledWith(true)
-  })
-
-  it('should stop listening when stopListening is called', async () => {
-    const { startListening, stopListening } = useServerLogs()
-
-    await startListening()
-    await stopListening()
-
-    expect(api.subscribeLogs).toHaveBeenCalledWith(false)
-  })
-
-  it('should register event listener when starting', async () => {
-    const { startListening } = useServerLogs()
-
-    await startListening()
-
-    expect(vi.mocked(useEventListener)).toHaveBeenCalledWith(
-      api,
-      'logs',
-      expect.any(Function)
-    )
-  })
-
-  it('should handle log messages correctly', async () => {
-    const { logs, startListening } = useServerLogs()
-
-    await startListening()
-
-    // Get the callback that was registered with useEventListener
-    const eventCallback = vi.mocked(useEventListener).mock.calls[0][2] as (
-      event: CustomEvent<LogsWsMessage>
-    ) => void
-
-    // Simulate receiving a log event
-    const mockEvent = new CustomEvent('logs', {
-      detail: {
-        type: 'logs',
-        entries: [{ m: 'Log message 1' }, { m: 'Log message 2' }]
-      } as unknown as LogsWsMessage
-    }) as CustomEvent<LogsWsMessage>
-
-    eventCallback(mockEvent)
-    await nextTick()
-
-    expect(logs.value).toEqual(['Log message 1', 'Log message 2'])
-  })
-
-  it('should use the message filter if provided', async () => {
-    const { logs, startListening } = useServerLogs({
-      messageFilter: (msg) => msg !== 'remove me'
-    })
-
-    await startListening()
-
-    const eventCallback = vi.mocked(useEventListener).mock.calls[0][2] as (
-      event: CustomEvent<LogsWsMessage>
-    ) => void
-
-    const mockEvent = new CustomEvent('logs', {
-      detail: {
-        type: 'logs',
-        entries: [
-          { m: 'Log message 1 dont remove me' },
-          { m: 'remove me' },
-          { m: '' }
-        ]
-      } as unknown as LogsWsMessage
-    }) as CustomEvent<LogsWsMessage>
-
-    eventCallback(mockEvent)
-    await nextTick()
-
-    expect(logs.value).toEqual(['Log message 1 dont remove me', ''])
-  })
-})