Add Cline provider adapter

## Goal Add Cline as a Lineage provider target. ## Why Cline is a common open-source agentic coding tool used inside editor workflows. It is a useful provider target for package materialization and local setup experiments. ## Scope - Define the Cline adapter boundary. - Determine which package assets map to Cline-compatible rules, MCP configuration, or workspace files. - Keep Cline-specific behavior out of core package semantics. - Add dry-run/inspect output showing what Cline support will do. ## Acceptance Criteria - Cline support is behind an explicit provider adapter. - Receiver-side writes are visible before apply. - Tests cover supported materialization behavior. - Docs explain expected local Cline setup and current limitations.