Summary

• Adds workspace cleanup safe as one DMC-owned safe cleanup entrypoint.
• Composes existing safe cleanup-eligible and active/no-signal drains, refuses force/unpushed discard, prunes stale DMC locks, and returns compact blockers.
• Adds focused standalone coverage for safe orchestration, lock pruning, repeated safe progress, and blocker summaries.

Closes #824.

Tests

• php -l inc/Workspace/WorkspaceSafeCleanupOrchestrator.php
• php -l inc/Cli/Commands/WorkspaceCommand.php
• php tests/workspace-safe-cleanup-orchestrator.php
• php tests/smoke-abandoned-cleanup-orchestrator.php
• php tests/smoke-cleanup-eligible-drain.php
• php tests/workspace-compact-output.php
• git diff --check

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 and OpenCode
• Used for: Implementing the safe cleanup entrypoint, focused tests, and verification.