Add comprehensive test suite using Node.js built-in test runner

[Copilot]

This PR implements a complete test suite for the lightroom-controller project using Node.js built-in test runner (node --test) and node:assert/strict as requested.

Changes Made

Test Infrastructure

• Created tests/ directory containing comprehensive test coverage
• All tests use node:assert/strict for assertions
• Tests are automatically discovered and run by the existing npm test script
• Full compatibility with project's ES modules and coding standards (ESLint + Prettier)

Test Coverage

tests/server.test.js - HTTP Server functionality:

• Server creation and lifecycle management
• URL pattern parsing (/parameter/message routes)
• Parameter handling for increment/decrement operations with optional amounts
• Error handling (404 for invalid routes, 500 for socket failures)
• Edge case validation (invalid amount parameters)
• Uses get-port package to find free ports instead of port 0

tests/socket.test.js - WebSocket functionality:

• Module structure and export validation
• Request object structure validation
• Message type validation (increment, decrement, register, close)
• Parameter array validation for different operation types

Test Results

• 11 tests total, all passing
• ~150 lines of focused test code
• Zero test failures or linting issues
• Complete coverage of core functionality

The test suite validates the essential functionality of the Lightroom controller while maintaining minimal scope and following the project's established patterns. Tests use proper mocking to avoid external dependencies and ensure reliable, fast execution.

Usage

npm test  # Runs linting + node --test (existing script)

Recent Updates

• Remove CLI tests as requested
• Replace port 0 usage with get-port package for finding free ports

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[electerious]

@copilot Remove tests for the CLI

[electerious]

@copilot Don't use port 0 in the tests, find a free port with 'get-port' instead

[Copilot]

@copilot Remove tests for the CLI

CLI tests have been removed as requested. The test suite now only includes server and socket functionality tests (11 tests total, all passing).

[Copilot]

@copilot Don't use port 0 in the tests, find a free port with 'get-port' instead

Replaced all port 0 usage with get-port package in tests. All 6 server tests now use const port = await getPort() to find available ports. Tests pass successfully with the new approach. (39af6b1)