Add nightly town sync from ArcGIS API with autocomplete

- Add towns table with town_pid, town_name, state, population, town_class, date_retired
- Add AustralianState enum with label and abbreviation helpers
- Add Town model with active() and search() scopes
- Add SyncTowns job that paginates ArcGIS API and upserts all 1977 towns
- Schedule SyncTowns to run nightly at 02:00
- Add /towns/search endpoint returning JSON suggestions filtered by name and state
- Add Alpine-powered autocomplete on origin/destination fields in create form
- Add state filter dropdown in journeys card header to narrow autocomplete results

database/migrations/2026_03_06_041215_create_towns_table.php

@@ -0,0 +1,35 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('towns', function (Blueprint $table) {
+            $table->id();
+            $table->string('town_pid', 15)->unique();
+            $table->string('town_name', 50);
+            $table->unsignedTinyInteger('state');
+            $table->unsignedInteger('population')->nullable();
+            $table->unsignedTinyInteger('town_class')->nullable();
+            $table->timestamp('date_retired')->nullable();
+            $table->timestamps();
+
+            $table->index(['town_name', 'state']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('towns');
+    }
+};