fix(tests/cover): mock spawn via src/ relative path so threaded-pool dedup catches the prod instance

Both cover/type.test.mts and cover/code.test.mts used:

  vi.mock('@socketsecurity/lib/process/spawn/child')

That mock keys on the package-specifier resolution. Inside the
production source (src/cover/type.ts, src/cover/code.ts), the
import is relative:

  import { spawn } from '../process/spawn/child'

Under vitest's threaded pool, the two resolution paths land on
different module instances despite the alias collapsing them to
the same file. The mock applies to the package-path instance; the
production code uses the relative-path instance — uncoupled.

Fix matches the canonical pattern from
test/unit/releases/*.test.mts: mock via the src/ relative path so
both sides resolve to the same key in vitest's mock registry.

cover/type.test.mts: 4 previously-failing tests now pass (10/10).
cover/code.test.mts: 1 previously-failing test now passes (29/29).

Author: jdalton

test/unit/cover/code.test.mts

@@ -12,10 +12,14 @@ import path from 'node:path'
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
-vi.mock('@socketsecurity/lib/process/spawn/child')
-
-import { spawn } from '@socketsecurity/lib/process/spawn/child'
-import { getCodeCoverage } from '@socketsecurity/lib/cover/code'
+// Mock via the src/ relative path so vitest intercepts the same
+// module instance that src/cover/code.ts imports (which uses
+// relative paths internally). Package-specifier mocks don't survive
+// vitest's threaded-pool dedup gaps.
+vi.mock('../../../src/process/spawn/child')
+
+import { spawn } from '../../../src/process/spawn/child'
+import { getCodeCoverage } from '../../../src/cover/code'
 
 let tmpDir: string
 

test/unit/cover/type.test.mts

@@ -12,12 +12,15 @@
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
-// Mock spawn at the package specifier — src resolution is enabled in
-// vitest.config.mts via the 'source' export condition.
-vi.mock('@socketsecurity/lib/process/spawn/child')
+// Mock via the src/ relative path so vitest intercepts the same
+// module instance that src/cover/type.ts imports (which uses
+// relative paths internally). Package-specifier mocks don't survive
+// vitest's threaded-pool dedup gaps. See:
+// test/unit/releases/*.test.mts for the canonical pattern.
+vi.mock('../../../src/process/spawn/child')
 
-import { spawn } from '@socketsecurity/lib/process/spawn/child'
-import { getTypeCoverage } from '@socketsecurity/lib/cover/type'
+import { spawn } from '../../../src/process/spawn/child'
+import { getTypeCoverage } from '../../../src/cover/type'
 
 describe('cover/type', () => {
   beforeEach(() => {