Tailwind CSS v4.2.3：多项修复与规范化改进

Fixed

• Canonicalization: improve canonicalizations for tracking-* utilities by preferring non-negative utilities (e.g. -tracking-tighter → tracking-wider) (#19827)
• Fix crash due to invalid characters in candidate (exceeding valid unicode code point range) (#19829)
• Ensure query params in imports are considered unique resources when using @tailwindcss/webpack (#19723)
• Canonicalization: collapse arbitrary values into shorthand utilities (e.g. px-[1.2rem] py-[1.2rem] → p-[1.2rem]) (#19837)
• Canonicalization: collapse border-{t,b}-* into border-y-*, border-{l,r}-* into border-x-*, and border-{t,r,b,l}-* into border-* (#19842)
• Canonicalization: collapse scroll-m{t,b}-* into scroll-my-*, scroll-m{l,r}-* into scroll-mx-*, and scroll-m{t,r,b,l}-* into scroll-m-* (#19842)
• Canonicalization: collapse scroll-p{t,b}-* into scroll-py-*, scroll-p{l,r}-* into scroll-px-*, and scroll-p{t,r,b,l}-* into scroll-p-* (#19842)
• Canonicalization: collapse overflow-{x,y}-* into overflow-* (#19842)
• Canonicalization: collapse overscroll-{x,y}-* into overscroll-* (#19842)
• Read from --placeholder-color instead of --background-color for placeholder-* utilities (#19843)
• Upgrade: ensure files are not emptied out when killing the upgrade process while it's running (#19846)
• Upgrade: use config.content when migrating from Tailwind CSS v3 to Tailwind CSS v4 (#19846)
• Upgrade: never migrate files that are ignored by git (#19846)
• Add .env and .env.* to default ignored content files (#19846)
• Canonicalization: migrate overflow-ellipsis into text-ellipsis (#19849)
• Canonicalization: migrate start-full → inset-s-full, start-auto → inset-s-auto, start-px → inset-s-px, and start-<number> → inset-s-<number> as well as negative versions (#19849)
• Canonicalization: migrate end-full → inset-e-full, end-auto → inset-e-auto, end-px → inset-e-px, and end-<number> → inset-e-<number> as well as negative versions (#19849)
• Canonicalization: move the - sign inside the arbitrary value -left-[9rem] → left-[-9rem] (#19858)
• Canonicalization: move the - sign outside the arbitrary value ml-[calc(-1*var(--width))] → -ml-(--width) (#19858)
• Improve performance when scanning JSONL / NDJSON files (#19862)
• Support NODE_PATH environment variable in standalone CLI (#19617)