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.

app/Models/Application.php

@@ -772,6 +772,24 @@ class Application extends BaseModel
         return $this->settings->is_static ? [80] : $this->ports_exposes_array;
     }
 
+    public function detectPortFromEnvironment(?bool $isPreview = false): ?int
+    {
+        $envVars = $isPreview
+            ? $this->environment_variables_preview
+            : $this->environment_variables;
+
+        $portVar = $envVars->firstWhere('key', 'PORT');
+
+        if ($portVar && $portVar->real_value) {
+            $portValue = trim($portVar->real_value);
+            if (is_numeric($portValue)) {
+                return (int) $portValue;
+            }
+        }
+
+        return null;
+    }
+
     public function environment_variables()
     {
         return $this->morphMany(EnvironmentVariable::class, 'resourceable')