Track pi-tasklight MVP and npm package readiness

[revazi]

Context

pi-tasklight is the Pi-specific integration layer for Tasklight. It should stay separate from the generic Tasklight CLI repository.

Tasklight CLI responsibilities:

• run commands
• send desktop notifications
• own macOS/Linux notification providers
• own tmux/iTerm focus behavior

pi-tasklight responsibilities:

• provide Pi slash commands and extension behavior
• call the installed Tasklight CLI
• avoid adding notification-provider logic directly
• keep Pi-specific docs/issues in this repository

MVP checklist

• Verify npm install path: pi install npm:@tasklight/pi-tasklight.
• Verify local path install: pi install ~/Work/pi-tasklight.
• Verify /tl, /tl-test, and /tl-toggle behavior.
• Verify Tasklight CLI resolution order:
  1. TASKLIGHT_BIN
  2. package dependency @tasklight/cli
  3. tasklight in PATH
  4. npx -y @tasklight/cli fallback
• Document compatibility with @tasklight/cli versions.
• Keep Tasklight CLI docs linking here, without duplicating Pi command details.

Acceptance criteria

• README clearly explains the separation from Tasklight CLI.
• Install and smoke-test instructions work for a fresh user.
• Tasklight CLI repository has no pi-tasklight implementation-tracking issues.