docs(03): create phase plans with research

Phase 03: Images
- 4 plans across 3 waves
- Sharp for thumbnails, native browser APIs for camera
- svelte-lightbox for fullscreen viewing
- Fix: 03-03 depends on 03-02 (needs uploadImage action)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.planning/phases/03-images/03-03-PLAN.md

@@ -3,7 +3,7 @@ phase: 03-images
 plan: 03
 type: execute
 wave: 2
-depends_on: ["03-01"]
+depends_on: ["03-02"]
 files_modified:
   - src/lib/components/CameraCapture.svelte
 autonomous: true