lint-mdx.js: multi-line opening tags (Card, CardGroup, etc.) silently skipped by attribute check

Bắt đầu trong scripts/lint-mdx.js tại checkMintlifyComponents và kiểm tra cách mỗi dòng được đối chiếu với regex của thẻ mở. Chạy linter trên các tệp MDX được nêu, sau đó xác minh rằng các thẻ Card nhiều dòng được kiểm tra, bao gồm một thẻ Card tổng hợp thiếu title=, trong khi các thẻ hợp lệ hiện có không tạo ra phát hiện mới.

Description

The opening-tag check in scripts/lint-mdx.js (checkMintlifyComponents) matches each line against a regex that expects the tag and its attributes on the same line. When a tag's name is on its own line, with attributes like title= spread across the following lines, the regex never matches - so the tag is silently skipped entirely. No required-attribute check runs, no CardGroup cols check runs, and it is not tracked for parent/child nesting rules.

Evidence

Found 5 multi-line opening tags across 2 files that were never being checked at all:

• docs/base-account/quickstart/ai-tools-available-for-devs.mdx - 3 multi-line Card tags (lines 10, 47, 67)
• docs/apps/resources/templates.mdx - 2 multi-line Card tags (lines 22, 28)

All 5 happen to already have a valid title= attribute, so this gap doesn't currently produce any wrong output in the lint report - but it means the linter would silently miss a genuinely missing title on any of these tags, or on any future multi-line tag written in this style.

Example (ai-tools-available-for-devs.mdx):
A Card tag opens on its own line, with title= and other attributes set on the following lines, closing several lines later. Because the check only reads the line containing <Card, it never sees the tag at all.

Fix

Companion PR makes the check accumulate lines starting at a lone opening-tag line until a closing > is found, then runs the existing regex against the accumulated text. Verified against all 5 real instances (no new findings, since they're all valid) and a synthetic multi-line Card missing title=, which is now correctly flagged.