Infinite Canvas — Phase 6: Helmor CLI canvas surface + orchestration

[Legacynnn]

Part of the Infinite Canvas epic: #61

Phase 6 — Helmor CLI canvas surface + agent orchestration

Make the canvas first-class for agents: an agent in a conversation panel can build and drive the canvas via the CLI.

Scope

• New helmor canvas subcommands in src-tauri/src/cli/ (reuse the Phase 1–3 domain commands; no logic duplication):
  • helmor canvas panel create|move|resize|list|delete
  • helmor canvas connect|disconnect
  • helmor canvas view (pan/zoom/translucency state)
• Each subcommand's --help includes copyable examples (matches existing CLI conventions).
• Agent orchestration over connections — a conversation panel connected to others can dispatch/manage them via the CLI (e.g. spawn a sibling conversation, connect it, send it a prompt). The conversation→conversation link from Phase 3 becomes operable end-to-end.
• Live canvas reflects CLI-driven mutations via UiMutationEvent (no app restart needed).

Out of scope

Browser/app panels (Phase 7).

Acceptance

• From a terminal/agent, helmor canvas can create, move, connect, and list panels and the running app updates live.
• An agent can spawn + connect + drive a sibling conversation panel via the CLI.
• CLI help blocks documented; lint/typecheck/test pass.