Agent PBX v0.6.0

Highlights

• Adds agent-pbx-tui, a TUI-only launcher for lightweight LAN clients with
  dotenv-style config at ~/.config/agent-pbx/tui.env.
• Adds low-power TUI watch mode, configurable refresh intervals, and updated
  tiny/mobile focus shortcuts for small terminals such as PocketCHIP.
• Improves remote TUI refresh by tailing current events and isolating the SSE
  event worker from other Textual refresh workers.
• Adds shared latest-report seen state so clearing NEW in one TUI clears it
  in other connected TUIs.
• Fixes no-report agents incorrectly appearing as NEW, and makes the tiny
  Agents view show Project directly after Status.
• Adds /v1/events?tail=true&limit=N for efficient latest-event reads and
  advances the database schema to version 7 with latest-report seen backfill.

Verification

• python -m pytest
• git diff --check
• PocketCHIP remote TUI probes for event refresh and shared NEW clearing