Add Windsurf provider adapter

## Goal Add Windsurf as a Lineage provider target. ## Why Windsurf is a widely used AI coding environment and should be considered for Lineage package activation where local config or workspace assets can be materialized safely. ## Scope - Define the Windsurf adapter boundary. - Determine whether Lineage should support command launch, editor/workspace materialization, or both. - Map supported package assets to Windsurf-compatible local files. - Keep Windsurf-specific behavior outside core package semantics. - Add dry-run/inspect output showing what Windsurf support will do. ## Acceptance Criteria - Windsurf support is behind an explicit provider adapter. - Receiver-side writes are visible before apply. - Tests cover supported materialization behavior. - Docs explain what is supported and what must still be configured by the user.