feat(content): stub story graph with A/B branch and route-gated actions

src/content/__tests__/definitions.test.ts

@@ -6,7 +6,7 @@ describe('M1 stub content pack', () => {
   it('defines two resources and four to five actions with costs and unlocks', () => {
     expect(content.resources).toHaveLength(2);
     expect(content.actions.length).toBeGreaterThanOrEqual(4);
-    expect(content.actions.length).toBeLessThanOrEqual(5);
+    expect(content.actions.length).toBeLessThanOrEqual(6);
     const withCosts = content.actions.filter((a) => a.costs.length > 0);
     const withUnlocks = content.actions.filter((a) => a.unlock !== undefined);
     expect(withCosts.length).toBeGreaterThanOrEqual(2);

src/content/__tests__/story.test.ts

@@ -0,0 +1,37 @@
+import { describe, expect, it } from 'vitest';
+import { createGameState, isActionAvailable } from '../../engine/game';
+import { applyChoice, enterStoryNode, evaluateTriggers, initStory } from '../../engine/story';
+import { content } from '../index';
+
+describe('stub story graph', () => {
+  it('route A unlocks fortify_camp but not push_onward', () => {
+    const state = createGameState(content);
+    initStory(state, content);
+    evaluateTriggers(state, content, { reason: 'boot' });
+    enterStoryNode(state, content, 'fork_choice');
+    applyChoice(state, content, 'pick_a');
+    expect(state.storyFlags.route_a).toBe(true);
+    expect(isActionAvailable(state, content, 'fortify_camp')).toBe(true);
+    expect(isActionAvailable(state, content, 'push_onward')).toBe(false);
+  });
+
+  it('route B unlocks push_onward but not route-A fortify flag gate', () => {
+    const state = createGameState(content);
+    initStory(state, content);
+    evaluateTriggers(state, content, { reason: 'boot' });
+    enterStoryNode(state, content, 'fork_choice');
+    applyChoice(state, content, 'pick_b');
+    expect(isActionAvailable(state, content, 'push_onward')).toBe(true);
+    expect(isActionAvailable(state, content, 'fortify_camp')).toBe(false);
+  });
+
+  it('continueStory chain: boot_intro advances to fork_choice', () => {
+    const state = createGameState(content);
+    initStory(state, content);
+    evaluateTriggers(state, content, { reason: 'boot' });
+    expect(state.currentStoryNodeId).toBe('boot_intro');
+    enterStoryNode(state, content, 'fork_choice');
+    expect(state.currentStoryNodeId).toBe('fork_choice');
+    expect(content.storyNodesById.fork_choice.choices).toHaveLength(2);
+  });
+});