feat: support onLog hook in dev

[NgoQuocViet2001]

Description

Adds Rollup-compatible onLog hook support to the dev plugin container.

• routes plugin debug, info, and warn calls through ordered onLog hooks
• supports filtering with false and re-emitting logs at another level
• preserves source-plugin metadata and Rollup's PLUGIN_LOG / PLUGIN_WARNING normalization
• applies the configured log level before evaluating lazy log factories
• gives options hooks their per-plugin minimal context
• maps Rolldown's generated LogLevel type through the existing Rolldown.* namespace so bundled type validation passes

Includes regression coverage for filtering, level changes, hook ordering and recursion, source metadata, options-hook logs, and lazy log evaluation.

Fixes #19937.

Validation

• corepack pnpm run build
• corepack pnpm exec vitest run packages/vite/src/node/server/__tests__/pluginContainer.spec.ts — 24/24 passed
• corepack pnpm exec eslint packages/vite/src/node/server/pluginContainer.ts packages/vite/src/node/server/__tests__/pluginContainer.spec.ts packages/vite/rolldown.dts.config.ts
• corepack pnpm exec oxfmt --check packages/vite/src/node/server/pluginContainer.ts packages/vite/src/node/server/__tests__/pluginContainer.spec.ts packages/vite/rolldown.dts.config.ts
• git diff --check

[NgoQuocViet2001]

Rebased onto the latest main and fixed the CI build failure. The generated Rolldown LogLevel type is now mapped through the existing Rolldown.* namespace, so bundled type validation passes. Local validation: full monorepo build, 24/24 focused tests, ESLint, and Oxfmt.

[NgoQuocViet2001]

CI retry is now green across Node 20/22/24/26, Ubuntu, macOS, and Windows, including lint and the full build/test matrix. The earlier Node 22 failure was a transient legacy watch test (legacy-styles-only-entry-watch.spec.ts) outside this PR's diff.