feat: add clip management with I/O marking, timeline markers, and clip list

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/lib/stores/clips.test.ts

@@ -0,0 +1,77 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import {
+  addClip,
+  removeClip,
+  updateClip,
+  markInPoint,
+  markOutPoint,
+  getClips,
+  getSelectedClipId,
+  getPendingInPoint,
+  clearAll,
+  selectClip,
+} from '$lib/stores/clips.svelte';
+
+describe('clip store', () => {
+  beforeEach(() => {
+    clearAll();
+  });
+
+  it('starts with no clips', () => {
+    expect(getClips()).toHaveLength(0);
+  });
+
+  it('adds a clip', () => {
+    addClip(10, 20);
+    const clips = getClips();
+    expect(clips).toHaveLength(1);
+    expect(clips[0].startTime).toBe(10);
+    expect(clips[0].endTime).toBe(20);
+    expect(clips[0].label).toBe('Clip 1');
+  });
+
+  it('removes a clip', () => {
+    addClip(10, 20);
+    const id = getClips()[0].id;
+    removeClip(id);
+    expect(getClips()).toHaveLength(0);
+  });
+
+  it('updates clip times', () => {
+    addClip(10, 20);
+    const id = getClips()[0].id;
+    updateClip(id, { startTime: 5 });
+    expect(getClips()[0].startTime).toBe(5);
+    expect(getClips()[0].endTime).toBe(20);
+  });
+
+  it('marks in-point and out-point to create a clip', () => {
+    markInPoint(15);
+    expect(getPendingInPoint()).toBe(15);
+    expect(getClips()).toHaveLength(0);
+
+    markOutPoint(25);
+    expect(getPendingInPoint()).toBeNull();
+    expect(getClips()).toHaveLength(1);
+    expect(getClips()[0].startTime).toBe(15);
+    expect(getClips()[0].endTime).toBe(25);
+  });
+
+  it('updates selected clip start when I is pressed', () => {
+    addClip(10, 20);
+    const id = getClips()[0].id;
+    selectClip(id);
+
+    markInPoint(5);
+    expect(getClips()[0].startTime).toBe(5);
+    expect(getPendingInPoint()).toBeNull();
+  });
+
+  it('swaps start/end if in-point is after out-point', () => {
+    markInPoint(30);
+    markOutPoint(10);
+    const clip = getClips()[0];
+    expect(clip.startTime).toBe(10);
+    expect(clip.endTime).toBe(30);
+  });
+});