Add Launcher resource for parameterized commands

[Copilot]

Adds a Launcher resource that accepts user input in the menu-bar popup and runs a configured command template with safe {input} substitution.

• Resource model

  • Adds launcher type and optional inputPlaceholder.
  • Preserves compatibility with existing configuration files.

• Execution

  • Adds runLauncher(_:input:).
  • Trims/rejects empty input, requires {input}, and shell-escapes all substitutions.

• UI and settings

  • Adds link indicator, compact text field, Go button, and Enter-key execution.
  • Adds Launcher to the resource editor with action-script and input-placeholder fields.

• Documentation

  • Documents Launcher behavior, schema fields, exit-code handling, and an MSX lookup example.

{
  "name": "MSX Lookup",
  "type": "launcher",
  "actionScript": "open \"https://example.com/search?q={input}\"",
  "inputPlaceholder": "Paste record ID"
}

• Fixes New resource type: Launcher — text input + Go button to open URLs or run parameterized commands #24