feat: add workspace Symphony dashboard

[Dimillian]

Summary

• add per-workspace Symphony runtime management, local task storage, and event plumbing
• add a dedicated Workspace Home Symphony dashboard, workflow editor, and sidebar status indicator
• generate Symphony workflows from workspace metadata and prefer a real git remote for automation clones

Validation

• npm run typecheck
• cd src-tauri && cargo check
• cd src-tauri && cargo test symphony_core --lib

Companion PR

• Symphony adapter/runtime changes: feat: add CodexMonitor tracker adapter symphony#1