fix(docs): deploy corrected active tabs

What changed

• use the brand color for active code-group tab labels while retaining the single inset indicator
• restore the bunpress.org config imports after the monorepo move
• deploy the generated docs to the existing S3 bucket after main-branch CI succeeds
• invalidate the bunpress.org CloudFront distribution after upload
• add a regression test that prevents the duplicate active-tab treatment from returning

Why

Production was still serving a January build whose HTML contained both an active button border and an active pseudo-element. The repository source had removed the duplicate style, but there was no push-to-deploy job to publish it. The moved site config also still imported the deleted root src directory, which would have dropped the production canonical URL, sitemap, and analytics settings in CI.

Impact

A successful push to main now publishes the current docs build to bunpress.org. Active package-manager tabs have one clean indicator and a branded label.

Validation

• bun run lint
• bun run build
• cd packages/bunpress && bun run typecheck
• bun test (540 passing)
• bun run build:docs
• generated HTML contains one active-tab rule, bunpress.org canonical URLs, the sitemap, and Fathom configuration