migrate: rewrite `tsdown/client` and `vite/client` in TS imports and tsconfig.json `types` array

[naokihaba]

Description

When running vp migrate, tsdown is removed as a dependency and replaced with vite-plus equivalents.
However, two patterns are currently left unrewritten, causing broken imports and TypeScript errors after migration.

relates: #1501

Cases to handle

1. import "tsdown/client" in .ts files

// before
import "tsdown/client";

// after
import "vite-plus/pack/client";

Real-world example: https://github.com/Tarrowren/css-class-intellisense/c91dd77dc1fb5acf/lezer/less/test/test-less.ts#L1

2. types array in tsconfig.json

// before
{ "compilerOptions": { "types": ["tsdown/client"] } }
{ "compilerOptions": { "types": ["vite/client"] } }

// after
{ "compilerOptions": { "types": ["vite-plus/pack/client"] } }
{ "compilerOptions": { "types": ["vite-plus/client"] } }

Real-world example: https://github.com/ascorbic/cirrus/blob/98aec98dc56de58f8d6010565cef6cfc5c62311e/packages/pds/tsconfig.json#L5

Suggested solution

Case 1 — import in .ts files

Add a new ast-grep rule to REWRITE_TSDOWN_RULES (import_rewriter.rs)
to match import "tsdown/client" and rewrite it to import "vite-plus/pack/client",
alongside the existing tsdown rule.

Case 2 — tsconfig.json types array

Add a new function to packages/cli/src/utils/tsconfig.ts using the existing
jsonc-parser dependency to rewrite entries in compilerOptions.types:

• "tsdown/client" → "vite-plus/pack/client"
• "vite/client" → "vite-plus/client"

Call this function from migrator.ts alongside cleanupDeprecatedTsconfigOptions().

Alternative

• Document as manual steps instead of automating. (Even though I don't want to)

Additional context

No response

Validations

• Read the Contributing Guidelines.
• Confirm this request is for Vite+ itself and not for Vite, Vitest, tsdown, Rolldown, or Oxc.
• Check that there isn't already an issue requesting the same feature.