fix(migration): only manage pnpm allowBuilds when webdriverio is used

edgedriver/geckodriver reach a project's dependency tree solely through the
opt-in webdriverio Vitest browser provider, which is an OPTIONAL peer of both
vite-plus and vitest (peerDependenciesMeta.optional). pnpm's autoInstallPeers
never installs an optional peer, so a non-webdriverio project never installs
those drivers — the `allowBuilds.<driver>: false` default-deny the migrator
wrote for every pnpm v10 project was inert config.

Make the migrator hands-off: when the project does not use webdriverio it now
writes nothing to allowBuilds and leaves any user-authored entry (their own
build-script trust decision) untouched. The webdriverio-present path still
writes `true` — load-bearing, since those drivers really install and their
postinstall must run, and it still overwrites a stale `false` when webdriverio
is added later.

This also drops the stale-`false` cleanup that, with the default-deny gone,
could delete a user's intentional `false` and could orphan a YAML anchor/alias
on deletion (crashing serialization). The now-unused directDriverDeps
collection/threading (collectDirectDriverDeps, collectWorkspaceDirectDriverDeps,
hasOwnDriverPostinstallDependency) is removed.

64 migration snaps drop the inert allowBuilds block; the one webdriverio fixture
keeps `true`. 220 migrator + 718 vite-plus src tests pass; vp check clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Brooooooklyn

packages/cli/snap-tests-global/migration-add-git-hooks/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-auto-create-vite-config/snap.txt

@@ -59,9 +59,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-baseurl-tsconfig/snap.txt

@@ -62,9 +62,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-chained-lint-staged-pre-commit/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-composed-husky-custom-dir/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-composed-husky-prepare/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-env-prefix-lint-staged/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-eslint-lint-staged/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-eslint-lintstagedrc/snap.txt

@@ -29,9 +29,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'

packages/cli/snap-tests-global/migration-eslint-npx-wrapper/snap.txt

@@ -34,9 +34,6 @@ catalog:
   vite: npm:@voidzero-dev/vite-plus-core@latest
   vitest: <semver>
   vite-plus: latest
-allowBuilds:
-  edgedriver: false
-  geckodriver: false
 overrides:
   vite: 'catalog:'
   vitest: 'catalog:'