feat: UI interaction polish — exit animations, hover effects, directional transitions

- Add AnimatedPanel component with CSS transition-based enter/exit for
  Profile popover and Notification panel (140ms scale+fade)
- Add nav-activate-pulse animation for floating-nav active indicator (320ms glow)
- Add tool-panel-fade-in crossfade when switching ecommerce tools
- Add carousel-card-label slide-up-in 260ms on active carousel card
- Add feature-visual img hover scale(1.03)+brightness, experience-route hover translateY(-2px)
- Add community-case-card--mosaic hover scale(1.02)+shadow lift
- Add directional PageTransition: forward→slideX(20px), backward→slideX(-20px)
- Move vite proxy target from hardcoded IP to VITE_DEV_PROXY env variable
- Add .env.example for developer onboarding

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/features/home/HomePage.tsx

@@ -266,6 +266,7 @@ function HomePage({ onOpenGenerate, onOpenEcommerce, onOpenScriptReview, onOpenT
                       }}
                     >
                       <img src={slide.imageUrl} alt={slide.title} />
+                      {isActive ? <span className="omni-home__carousel-card-label slide-up-in-260">{slide.title}</span> : null}
                     </button>
                   );
                 })}