fix(vtz): vi.mock propagates through transitive imports (resolves #2731)

[viniciusdacal]

Summary

Closes #2731. Three layered fixes so vi.mock('m', factory) reaches production code that uses await import('m') deep in the dependency graph:

1. Wrap dynamic import() in non-test files when spy_exports is on. The mock-hoisting pass already wrapped them in test files via __vertz_unwrap_module; extending the wrap to the entire graph means cli.ts → await import('@vertz/compiler') no longer bypasses the spy installed by cli.test.ts. The __vertz_unwrap_module helper caches by the original (frozen) module identity via WeakMap, so the test file and production code resolve to the same mutable wrapper.

2. mockRestore on mock(impl) now restores the initial impl instead of clearing it. Matches vitest semantics ("for vi.fn(impl), mockRestore reverts to impl") and unbreaks the common vi.mock('m', () => ({ fn: mock(() => obj) })) + vi.restoreAllMocks() pattern, where the factory contract was being torn down on first afterEach. mockReset still clears.

3. Mock proxy module unions in synthetic-polyfill exports for bare specifiers like esbuild + node:*. Without this, transitive import { transformSync } from 'esbuild' in @vertz/ui-server/bun-plugin failed at link time even when the call path never invoked it at runtime.

Unskips the 3 test blocks parked on this:

• packages/cli/src/tests/cli.test.ts — codegen command action (3 tests)
• packages/cli/src/production-build/tests/orchestrator.test.ts — BuildOrchestrator (23 tests)
• packages/cli/src/production-build/tests/ui-build-pipeline.test.ts — buildUI (47 tests)

Test mocks updated to use factory-supplied impls (mock(async () => x)) instead of mock().mockResolvedValue(x) so they survive vi.restoreAllMocks() under correct vitest semantics — the runtime fix preserves initialImpl, but the previous test code also relied on configured impls surviving reset (which neither vitest nor vtz does for mock() with no initial impl).

Public API Changes

• mockRestore() on a mock created via mock(impl) now restores impl instead of clearing the implementation. Behavior change for callers that depended on mockRestore being identical to mockReset for non-spy mocks. mockReset() semantics unchanged. Aligns with vitest.
• Dynamic import() in non-test files compiled under vtz test is now wrapped with __vertz_unwrap_module. Transparent at runtime — the wrapper proxies reads to the original namespace and stores writes locally.
• Mocked modules with synthetic vtz polyfills (esbuild, node:*) now expose the union of polyfill exports + factory-returned exports + on-disk ESM exports.

Test plan

• cargo test -p vertz-compiler-core — 1247 passed
• cargo test --release -p vtz --lib — 3460 passed (incl. 3 new mock_restore + dynamic-import wrap regression tests)
• cargo clippy --all-targets -- -D warnings — clean
• cargo fmt --all -- --check — clean
• vtz test src/__tests__/cli.test.ts — 63/63 pass
• vtz test src/production-build/__tests__/orchestrator.test.ts — 23/23 pass
• vtz test src/production-build/__tests__/ui-build-pipeline.test.ts — 47/47 pass (1 brotli skip, vtz polyfill gap, tracked separately)
• Full workspace vtz test — no new regressions vs main; remaining failures (SSR examples, AOT JSX subprocess tests, packages that import bun) are pre-existing.

🤖 Generated with Claude Code