effectify LSP service

[kitlangton]

Summary

• Migrate LSP from legacy Instance.state() to the Effect service pattern (Interface, Service, layer, async facades via runPromiseInstance)
• Wire LSP.Service into InstanceServices union and lookup() in instances.ts
• Add runSyncInstance helper to runtime.ts
• Mark LSP as done in the migration spec

Details

• State (clients, servers, broken, spawning) is held as closure variables in the layer
• Server config loading runs in the layer body via Effect.promise
• Cleanup (shutting down all LSP clients) uses Effect.addFinalizer
• All public functions remain as async facades with identical signatures
• Instance.directory replaced with directory captured from InstanceContext

Test plan

• bun run typecheck in packages/opencode -- no new errors (pre-existing Effect version mismatch errors remain, same as File/Skill/etc.)
• Grep confirms Instance.state is fully removed from lsp/index.ts
• Manual smoke test: LSP features (hover, diagnostics, go-to-definition) work as before