feat: step-based missions around park machines with 3D objective arrow

Phase 5 of turning the game into the company landing page.

- Replace purchase-only missions with a data-driven list of short step
  chains (goto, locate on map, inspect, order, buy, buy at N places)
  in src/game/missions, with pure progress logic on the game state.
- Six missions, most about machines installed in Park Mellat; add two
  sites there (lake and sports fields) and record the product model
  installed at every site.
- Inspecting a machine opens a machine card with the installed model,
  specs, price, an order request and sales contact.
- The objective chip shows the current step; the missions sheet lists
  missions with the current one's steps ticked; a brand-coloured arrow
  hovers over the target machine.
- Rewards and banners per finished mission, the next step is spoken.
- Tests for mission data, step logic, text and the machine card.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/missions.test.js

@@ -0,0 +1,97 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createState, purchase } from '../src/game/economy/gameState.js';
+import { machineById, machines } from '../src/constants/locations.js';
+import { MISSIONS } from '../src/game/missions/missions.js';
+import {
+  applyMissionEvent,
+  currentMission,
+  currentStep,
+  stepTarget,
+} from '../src/game/missions/missionProgress.js';
+import { currentStepText, missionListItems } from '../src/game/missions/missionText.js';
+import { strings } from '../src/i18n/fa.js';
+
+/**
+ * Buys water at a machine and reports the purchase to the missions.
+ * @param {object} state - Game state.
+ * @param {string} id - Machine id.
+ * @returns {object} Mission event result.
+ */
+function buyAt(state, id) {
+  state.minutes = 12 * 60;
+  purchase(state, machineById(id), 'water');
+  return applyMissionEvent(state, { type: 'buy', machineId: id });
+}
+
+test('Every mission step points at a real machine and has text', () => {
+  for (const mission of MISSIONS) {
+    assert.ok(strings.missions[mission.id], `title for ${mission.id}`);
+    for (const step of mission.steps) {
+      assert.ok(strings.steps[step.type], `text for ${step.type}`);
+      if (step.target) assert.ok(machineById(step.target), `machine ${step.target}`);
+    }
+  }
+  const parkSites = machines.filter((m) => m.category === 'park').map((m) => m.id);
+  assert.deepEqual(parkSites, ['mellat-park', 'mellat-lake', 'mellat-sports']);
+  const parkMissions = MISSIONS.filter((m) => m.steps.some((s) => parkSites.includes(s.target)));
+  assert.ok(parkMissions.length > MISSIONS.length / 2, 'most missions are about park machines');
+});
+
+test('The first mission is: go to the factory, then buy there', () => {
+  const state = createState();
+  assert.equal(currentMission(state).id, 'firstBuy');
+  assert.equal(currentStepText(state), strings.steps.goto(machineById('factory').name));
+  assert.equal(buyAt(state, 'factory').stepDone, false, 'buying before arriving does not count');
+  assert.deepEqual(applyMissionEvent(state, { type: 'arrive', machineId: 'factory' }), {
+    stepDone: true,
+    mission: null,
+  });
+  const balance = state.balance,
+    xp = state.xp;
+  const result = buyAt(state, 'factory');
+  assert.equal(result.mission.id, 'firstBuy');
+  assert.equal(state.xp, xp + result.mission.reward.xp);
+  assert.ok(state.balance > balance, 'reward paid after the purchase');
+  assert.deepEqual(state.missionsDone, ['firstBuy']);
+  assert.equal(stepTarget(state), 'mellat-park');
+});
+
+test('Park missions chain locate, goto, inspect, order and buy steps', () => {
+  const state = createState();
+  state.missionIndex = 1;
+  const steps = [
+    ['locate', 'mellat-park'],
+    ['arrive', 'mellat-park'],
+  ];
+  for (const [type, machineId] of steps) applyMissionEvent(state, { type, machineId });
+  assert.equal(applyMissionEvent(state, { type: 'buy', machineId: 'mellat-lake' }).stepDone, false);
+  assert.equal(buyAt(state, 'mellat-park').mission.id, 'parkGate');
+  applyMissionEvent(state, { type: 'arrive', machineId: 'mellat-lake' });
+  assert.equal(currentStep(state).type, 'inspect');
+  assert.equal(
+    applyMissionEvent(state, { type: 'inspect', machineId: 'mellat-lake' }).mission.id,
+    'parkLake',
+  );
+  applyMissionEvent(state, { type: 'arrive', machineId: 'mellat-sports' });
+  applyMissionEvent(state, { type: 'inspect', machineId: 'mellat-sports' });
+  assert.equal(
+    applyMissionEvent(state, { type: 'order', machineId: 'mellat-sports' }).mission.id,
+    'parkSports',
+  );
+  buyAt(state, 'mellat-lake');
+  assert.equal(buyAt(state, 'mellat-sports').mission.id, 'parkTour');
+});
+
+test('The explorer mission counts different city machines and shows progress', () => {
+  const state = createState();
+  state.missionIndex = MISSIONS.findIndex((m) => m.id === 'explorer');
+  for (const id of ['mellat-park', 'mellat-lake', 'ferdowsi-university', 'azadi-metro'])
+    assert.equal(buyAt(state, id).stepDone, false);
+  assert.ok(currentStepText(state).includes('۴'));
+  assert.equal(buyAt(state, 'factory').stepDone, false, 'the factory does not count');
+  assert.equal(buyAt(state, 'mellat-sports').mission.id, 'explorer');
+  assert.equal(currentStepText(state), strings.steps.allDone);
+  const items = missionListItems(state);
+  assert.ok(items.every((item) => !item.active && item.steps.length === 0));
+});