fix: Respect file exclusions when discovering tsconfig files

[rifont]

When tailwindCSS.files.exclude is configured, tsconfig discovery still parses excluded tsconfig.json and jsconfig.json files. In larger monorepos this can surface repeated EXTENDS_RESOLVE noise and add unnecessary project resolution work.

This change forwards tailwindCSS.files.exclude into the resolver and applies it while collecting configs and referenced projects. It also handles root-relative (repos/**), root-anchored (/repos/**), and absolute path patterns, with a regression test that covers all three.

Test plan

• pnpm --filter @tailwindcss/language-server test run src/resolver/tsconfig.test.ts
• pnpm --filter @tailwindcss/language-server build
• pnpm --filter vscode-tailwindcss run _esbuild --minify
• Verified in a local Cursor workspace that Tailwind initialization no longer scans repos/** (a large directory with 100+ git cloned repositories)

AI Disclosure

• AI assistance used: yes
• Model: gpt-5.3-codex-xhigh
• Scope: implementation support, regression test authoring, and PR drafting
• Human verification: manually reviewed diff and validated test/build commands and extension logs