Migrate 16 direct Instance.directory/worktree/project reads inside
Effect code to use InstanceState.directory/context helpers that check
the InstanceRef first and fall back to ALS.
- Export InstanceState.directory and InstanceState.context helpers
- bus/index.ts: GlobalBus.emit uses InstanceState.directory
- session/prompt.ts: 5 callsites migrated to InstanceState.context
- session/index.ts: 4 callsites migrated
- session/compaction.ts: 1 callsite migrated
- config/config.ts: 1 callsite migrated
- format/index.ts: 1 callsite migrated
- worktree/index.ts: 5 callsites migrated
- storage/db.ts: Database.effect preserves Instance ALS via Instance.bind
- test/lib/llm-server.ts: add wait/hold/fail SSE stream support
- Remove most provideInstance(dir) wrappers from prompt tests
(5 remain due to Instance.state sync ALS dependency)
cc412f3014