v0.1.19

Changelog

• 7084dae: Add workspaces, and message any agent with your login (@nskpaun)
• d66c465: Address review: lookup errors, cold-start on --wait 0, flag validation (@nskpaun)
• 5f3b13b: Drop the discarded pre-send thread walk (staticcheck SA4006) (@nskpaun)
• c1f5611: Merge pull request #42 from chariots-sh/claude/workspaces-and-messaging (@nskpaun)