feat(game): NAVIGATION AI unlocks two-hop jumps in one action (#35)

e2e/smoke.spec.ts

@@ -117,16 +117,21 @@ test('tab bar stays pinned while panel content scrolls (#31)', async ({ page })
 
 test('world map shows the generated starting system and its neighbours', async ({ page }) => {
   const world = (await (await page.request.get('/api/world')).json()) as WorldState;
+  // #35 — once NAVIGATION AI is researched the chart also offers two-hop systems, so the expected
+  // button count depends on the save's tech state (the CI DB persists across retries).
+  const techs = (await (await page.request.get('/api/tech')).json()) as { slug: string; state: string }[];
+  const maxHops = techs.some((t) => t.slug === 'NAV_AI' && t.state === 'RESEARCHED') ? 2 : 1;
 
   await page.goto('/');
   // Live chart title carries the turn counter.
   await expect(page.getByText(/GALACTIC CHART \/\/ JUMP ROUTES — TURN \d+/)).toBeVisible();
-  // The current system is marked, and every adjacent system is a clickable chart field (role=button).
+  // The current system is marked, and every in-range system is a clickable chart field (role=button).
   const current = world.systems.find((s) => s.current)!;
   await expect(page.getByText('CURRENT', { exact: true })).toBeVisible();
   const panel = page.getByRole('tabpanel');
-  const adjacent = world.edges.filter(([a, b]) => a === current.id || b === current.id); // six on a fresh save
-  await expect(panel.getByRole('button')).toHaveCount(adjacent.length);
+  // Six on a fresh save without NAV AI; the two-hop ring joins once it is researched.
+  const jumpable = world.systems.filter((s) => s.id !== current.id && shortestJumpPath(current.id, s.id, world.edges).length <= maxHops);
+  await expect(panel.getByRole('button')).toHaveCount(jumpable.length);
 });
 
 test('jumping to an adjacent system updates the world state and turn counter', async ({ page }) => {
@@ -364,6 +369,67 @@ test('SKILL TREE tab researches WEAPONS SYSTEMS and unlocks the gated WEAPONS bu
   await expect(weaponsCard.getByText('LV 1')).toBeVisible();
 });
 
+test('NAVIGATION AI research unlocks two-hop jumps on the world map (#35)', async ({ page }) => {
+  // Research costs two resources (70% of scans drop one), so a short scan loop makes it affordable;
+  // jumping keeps it going if a system exhausts. Idempotent: a retry finds it already RESEARCHED.
+  let techs = (await (await page.request.get('/api/tech')).json()) as { id: number; slug: string; state: string }[];
+  const navAiState = () => techs.find((t) => t.slug === 'NAV_AI')!.state;
+  if (navAiState() !== 'RESEARCHED') {
+    let ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+    let iterations = 0;
+    while (totalQty(ship.inventory, 'resource') < 2 && iterations < 40) {
+      iterations++;
+      const sys = (await (await page.request.get('/api/system')).json()) as SystemState;
+      const unexplored = sys.planets.filter((p) => !p.explored);
+      if (unexplored.length > 0) {
+        expect((await page.request.post('/api/explore', { data: { planetId: unexplored[0].id } })).status()).toBe(200);
+      } else {
+        await jumpToFreshSystem(page); // prefer undiscovered territory — first-edge ping-pongs between exhausted systems
+      }
+      ship = (await (await page.request.get('/api/ship')).json()) as ShipState;
+    }
+    expect(totalQty(ship.inventory, 'resource')).toBeGreaterThanOrEqual(2);
+
+    await page.goto('/');
+    // SKILL TREE tab: research NAVIGATION AI (two resources) — the card flips to RESEARCHED.
+    await page.getByRole('tab', { name: 'SKILL TREE' }).click();
+    const techCard = page.getByRole('heading', { name: 'NAVIGATION AI' }).locator('xpath=ancestor::div[3]');
+    await expect(techCard.getByText('AVAILABLE')).toBeVisible(); // root tech — no prerequisites
+    await expect(techCard.getByRole('button', { name: 'RESEARCH' })).toBeEnabled(); // resources ≥ 2
+    await techCard.getByRole('button', { name: 'RESEARCH' }).click();
+    await expect(techCard.getByText('RESEARCHED')).toBeVisible();
+  }
+
+  // Pick a system exactly two hops from the current one. A completely fresh save has none (the start
+  // region is only one hop deep), so jump once first — that expansion creates the two-hop territory.
+  let world = (await (await page.request.get('/api/world')).json()) as WorldState;
+  const findTwoHop = () => {
+    const currentId = world.systems.find((s) => s.current)!.id;
+    return world.systems.find((s) => shortestJumpPath(currentId, s.id, world.edges).length === 2);
+  };
+  let guard = 0;
+  while (!findTwoHop() && guard < 5) {
+    await jumpToFreshSystem(page); // +1 turn — jumping into undiscovered territory always expands the chart
+    world = (await (await page.request.get('/api/world')).json()) as WorldState;
+    guard++;
+  }
+  const target = findTwoHop()!;
+  expect(target).toBeDefined();
+
+  await page.goto('/'); // fresh chart with NAV AI researched — two-hop fields are clickable now
+  await expect(page.getByText(/GALACTIC CHART \/\/ JUMP ROUTES — TURN \d+/)).toBeVisible();
+  const panel = page.getByRole('tabpanel');
+  const turnBefore = world.turn;
+
+  // The two-hop systems render as distinct chart fields (// JUMP ×2 sublabel), and the target is one of them.
+  await expect(panel.getByText(/(DISCOVERED|UNKNOWN) \/\/ JUMP ×2/)).toBeVisible();
+  await panel.getByRole('button', { name: target.name.toUpperCase() }).click();
+
+  const after = (await (await page.request.get('/api/world')).json()) as WorldState;
+  expect(after.systems.find((s) => s.id === target.id)!.current).toBe(true); // world state updated in one action
+  expect(after.turn).toBe(turnBefore + 2); // the turn cost scales with hop count (#35)
+});
+
 test('MISSIONS tab accepts a contract and completing it grants the reward', async ({ page }) => {
   const board = (await (await page.request.get('/api/missions')).json()) as MissionDto[];
   expect(board.filter((m) => m.state === 'AVAILABLE').length).toBeGreaterThanOrEqual(3); // the board is always topped up