feat: add automated PORT environment variable detection and UI warnings

Add detection system for PORT environment variable to help users configure applications correctly:

- Add detectPortFromEnvironment() method to Application model to detect PORT env var
- Add getDetectedPortInfoProperty() computed property in General Livewire component
- Display contextual info banners in UI when PORT is detected:
  - Warning when PORT exists but ports_exposes is empty
  - Warning when PORT doesn't match ports_exposes configuration
  - Info message when PORT matches ports_exposes
- Add deployment logging to warn about PORT/ports_exposes mismatches
- Include comprehensive unit tests for port detection logic

The ports_exposes field remains authoritative for proxy configuration, while
PORT detection provides helpful suggestions to users.

tests/Unit/ApplicationPortDetectionTest.php

@@ -0,0 +1,156 @@
+<?php
+
+/**
+ * Unit tests for PORT environment variable detection feature.
+ *
+ * Tests verify that the Application model can correctly detect PORT environment
+ * variables and provide information to the UI about matches and mismatches with
+ * the configured ports_exposes field.
+ */
+
+use App\Models\Application;
+use App\Models\EnvironmentVariable;
+use Illuminate\Support\Collection;
+use Mockery;
+
+beforeEach(function () {
+    // Clean up Mockery after each test
+    Mockery::close();
+});
+
+it('detects PORT environment variable when present', function () {
+    // Create a mock Application instance
+    $application = Mockery::mock(Application::class)->makePartial();
+
+    // Mock environment variables collection with PORT set to 3000
+    $portEnvVar = Mockery::mock(EnvironmentVariable::class);
+    $portEnvVar->shouldReceive('getAttribute')->with('real_value')->andReturn('3000');
+
+    $envVars = new Collection([$portEnvVar]);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables')
+        ->andReturn($envVars);
+
+    // Mock the firstWhere method to return our PORT env var
+    $envVars = Mockery::mock(Collection::class);
+    $envVars->shouldReceive('firstWhere')->with('key', 'PORT')->andReturn($portEnvVar);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables')
+        ->andReturn($envVars);
+
+    // Call the method we're testing
+    $detectedPort = $application->detectPortFromEnvironment();
+
+    expect($detectedPort)->toBe(3000);
+});
+
+it('returns null when PORT environment variable is not set', function () {
+    $application = Mockery::mock(Application::class)->makePartial();
+
+    // Mock environment variables collection without PORT
+    $envVars = Mockery::mock(Collection::class);
+    $envVars->shouldReceive('firstWhere')->with('key', 'PORT')->andReturn(null);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables')
+        ->andReturn($envVars);
+
+    $detectedPort = $application->detectPortFromEnvironment();
+
+    expect($detectedPort)->toBeNull();
+});
+
+it('returns null when PORT value is not numeric', function () {
+    $application = Mockery::mock(Application::class)->makePartial();
+
+    // Mock environment variables with non-numeric PORT value
+    $portEnvVar = Mockery::mock(EnvironmentVariable::class);
+    $portEnvVar->shouldReceive('getAttribute')->with('real_value')->andReturn('invalid-port');
+
+    $envVars = Mockery::mock(Collection::class);
+    $envVars->shouldReceive('firstWhere')->with('key', 'PORT')->andReturn($portEnvVar);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables')
+        ->andReturn($envVars);
+
+    $detectedPort = $application->detectPortFromEnvironment();
+
+    expect($detectedPort)->toBeNull();
+});
+
+it('handles PORT value with whitespace', function () {
+    $application = Mockery::mock(Application::class)->makePartial();
+
+    // Mock environment variables with PORT value that has whitespace
+    $portEnvVar = Mockery::mock(EnvironmentVariable::class);
+    $portEnvVar->shouldReceive('getAttribute')->with('real_value')->andReturn('  8080  ');
+
+    $envVars = Mockery::mock(Collection::class);
+    $envVars->shouldReceive('firstWhere')->with('key', 'PORT')->andReturn($portEnvVar);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables')
+        ->andReturn($envVars);
+
+    $detectedPort = $application->detectPortFromEnvironment();
+
+    expect($detectedPort)->toBe(8080);
+});
+
+it('detects PORT from preview environment variables when isPreview is true', function () {
+    $application = Mockery::mock(Application::class)->makePartial();
+
+    // Mock preview environment variables with PORT
+    $portEnvVar = Mockery::mock(EnvironmentVariable::class);
+    $portEnvVar->shouldReceive('getAttribute')->with('real_value')->andReturn('4000');
+
+    $envVars = Mockery::mock(Collection::class);
+    $envVars->shouldReceive('firstWhere')->with('key', 'PORT')->andReturn($portEnvVar);
+    $application->shouldReceive('getAttribute')
+        ->with('environment_variables_preview')
+        ->andReturn($envVars);
+
+    $detectedPort = $application->detectPortFromEnvironment(true);
+
+    expect($detectedPort)->toBe(4000);
+});
+
+it('verifies ports_exposes array conversion logic', function () {
+    // Test the logic that converts comma-separated ports to array
+    $portsExposesString = '3000,3001,8080';
+    $expectedArray = [3000, 3001, 8080];
+
+    // This simulates what portsExposesArray accessor does
+    $result = is_null($portsExposesString)
+        ? []
+        : explode(',', $portsExposesString);
+
+    // Convert to integers for comparison
+    $result = array_map('intval', $result);
+
+    expect($result)->toBe($expectedArray);
+});
+
+it('verifies PORT matches detection logic', function () {
+    $detectedPort = 3000;
+    $portsExposesArray = [3000, 3001];
+
+    $isMatch = in_array($detectedPort, $portsExposesArray);
+
+    expect($isMatch)->toBeTrue();
+});
+
+it('verifies PORT mismatch detection logic', function () {
+    $detectedPort = 8080;
+    $portsExposesArray = [3000, 3001];
+
+    $isMatch = in_array($detectedPort, $portsExposesArray);
+
+    expect($isMatch)->toBeFalse();
+});
+
+it('verifies empty ports_exposes detection logic', function () {
+    $portsExposesArray = [];
+
+    $isEmpty = empty($portsExposesArray);
+
+    expect($isEmpty)->toBeTrue();
+});