Implement PlanSyncClient for synchronizing local resources with a remote
CleverAgents server and submitting plans for remote execution:
- Sync actions, skills, tools, projects with configurable scope flags
- Conflict resolution policies (local_wins / server_wins)
- Remote plan execution, apply, and status query endpoints
- Server-side ID persistence in local item metadata
- Sync summary output (created/updated/skipped/errors)
- Dry-run mode that skips server mutations
- SyncScope, SyncSummary, ExecutionResult data models
- Behave scenarios (18 scenarios, 62 steps)
- Robot Framework smoke tests
- ASV benchmark for sync throughput baseline
- Reference documentation at docs/reference/server_sync.md
ISSUES CLOSED: #336
