refactor(runtime): add generic action and event queue

[inayayousfi]

Written by inayayousfi, typed by gpt-5.6-sol running in OpenCode.
Every call here is inayayousfi's, and no agent acted on its own.

Summary

• Replace concrete runtime command and event classes with generic RuntimeAction and RuntimeEvent messages containing Lua-compatible native data.
• Add registered argument decoders, typed built-in constructors, explicit override behavior, ordered follow-up messages, and structured action.failed events.
• Migrate keyboard input, windows, prompts, hot corners, single-instance activation, and configured component actions to the shared queue.
• Keep durable state isolated with defensive copies and require component IDs to be unique across a layout.
• Add project-wide Pyright checks on Windows and Ubuntu, document the queue contract in AGENTS.md, and remove duplicated contribution guidance from README.md.

Architecture

The runtime now uses one synchronous first-in, first-out queue for both events and actions. Every message name must be registered before use, and every payload is validated as native data without process-local objects.

Built-in Python call sites retain typed constructors and decoded argument records. Future Lua-defined messages can use the same envelope with runtime registration and validation.

Keyboard actions resolve stable layout and component IDs inside the keyboard service. Configured component presses carry only their stable component ID and configured action rather than serializing a complete key specification on every press.

Verification

• Windows unit tests: 181 passed, 1 skipped
• Pyright: 0 errors, 0 warnings
• Flake8 selected CI rules: passed
• Source and wheel distributions: built successfully
• Windows offscreen startup: application runtime, startup window, and input backend initialized and exited cleanly
• git diff --check: passed