chore: modernize dev tooling and CI (TypeScript 7, vitest, oxlint, codecov, Node 22-26)

[B4nan]

The dev toolchain was stuck on TypeScript 4, ESLint 7 and Jest 27 with a Node 10 to 14 CI matrix, so every Renovate major bump failed. This updates all of it at once and supersedes the open Renovate PRs.

• CI runs on Node 22, 24 and 26 with actions/checkout@v7, actions/setup-node@v7 and editorconfig-checker 4. Coverage goes to codecov (replacing coveralls) from the Node 24 job only.
• TypeScript 7. Its tsc works fine, but the compiler API is gone, so ts-jest and ts-node had to go: tests run on vitest 5 (same as the main repo) and the copy script is now plain JS. tsconfig.json drops the removed suppressImplicitAnyIndexErrors, baseUrl and moduleResolution: node10 options and sets rootDir explicitly.
• ESLint and typescript-eslint are replaced by oxlint, same as in the main repo, because typescript-eslint also needs the TS compiler API. The rule set is the old one without the pure formatting rules.
• rimraf 6, @types/node 24. Snapshots are regenerated in the vitest format (different key naming and string escaping). The highlighted output itself is unchanged.
• packageManager is pinned to yarn 1.22.22 so corepack does not pick yarn 4 for a v1 lockfile.

Only dev dependencies and tooling change, no release needed.

[coveralls]

Coverage Report for CI Build 33967305323

Coverage increased (+3.3%) to 97.462%

Details

• Coverage increased (+3.3%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 3 coverage regressions across 2 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

3 previously-covered lines in 2 files lost coverage.

File	Lines Losing Coverage	Coverage
src/Tokenizer.ts	2	97.47%
src/SqlHighlighter.ts	1	97.06%

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Coverage Stats

Relevant Lines:	113
Covered Lines:	110
Line Coverage:	97.35%
Relevant Branches:	84
Covered Branches:	82
Branch Coverage:	97.62%
Branches in Coverage %:	Yes
Coverage Strength:	1653.84 hits per line

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💛 - Coveralls