Fix gotoLocation message type

[liurenfeng94-ops]

Fixes a small shared message type mismatch.

GotoLocation was inferred from gotoPosition, so the exported TypeScript type had pos instead of the line and character fields that the gotoLocation schema accepts. This points the type alias at the matching schema and adds a small regression test around the message shape.

Validation:

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

[github-actions]

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[liurenfeng94-ops]

Thanks — I rewrote the description to be clearer. This is just a type alias fix: the runtime schema already uses line/character, but the exported TypeScript type was pointing at the position message by mistake.