Implement BMad-style IDE handler architecture for WDS:
- Base class (_base-ide.js) with template method pattern
- Dynamic handler discovery via IdeManager
- Priority handlers: Windsurf, Cursor, Claude Code, Cline, GitHub Copilot
- Installer integration after agent compilation step
- Saga activation now branches on starting_point config (pitch vs brief)
- Remove parenthetical hint from learning material prompt
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>