Fix Rift workspace path resolution and rollback

[dbpolito]

Ticket

SKIPPED

Description

Resolve Rift workspaces from the stable OpenCode project checkout so named workspaces use Rift's expected sibling location instead of nesting beneath another managed workspace. Make workspace setup transactional by removing partial resources on creation, session, or ownership failures, and collapse duplicate managed-workspace listings.

Checklist

Workspace Resolution

• Resolve Rift registration from the stable project checkout
• Verify Rift creation matches the directory registered by OpenCode
• Preserve Rift's native destination selection

Failure Recovery

• Roll back partial Rift and native worktree creation
• Reject foreign project ownership before creating a session
• Report expected and actual ownership when validation fails

Workspace Discovery

• Deduplicate managed workspace entries by normalized directory
• Return the Rift workspace ID after successful creation

Validation

• Verify that bun run compile succeeds
• Confirm that bun run typecheck reports no errors
• Check that all 80 tests pass with bun run test