Convert tsserver request locations to one based

[liurenfeng94-ops]

Fixes the location values sent to typescript.tsserverRequest.

TypeScript AST locations are zero-based, but tsserver protocol line and offset values are one-based. The realtime metrics matrix still keeps zero-based line/column values for VS Code diagnostics, but converts them before sending completion/quickinfo requests to tsserver.

Validation:

• pnpm vitest run test/tsserver-location.test.ts
• pnpm vitest run
• pnpm typecheck
• pnpm exec eslint .
• pnpm build

[github-actions]

We've flagged this as a potential contribution without a human behind it. We welcome the thoughtful use of AI tools when contributing, but ask all contributors to follow two core principles:

1. Never let an LLM speak for you - all comments, issues, and PR descriptions should be written in your own words, reflecting your own understanding.
2. Never let an LLM think for you - only submit contributions you fully understand and can explain.

Please review these AI-assisted contribution guidelines and update this contribution if needed.

If this was flagged in error, we apologise! 😳 Just let us know. 🙏

[liurenfeng94-ops]

Thanks — I checked the PR again and kept the description focused on the actual coordinate conversion. VS Code diagnostics still use zero-based ranges; only the tsserver request payload is converted.