Improve folder organization and code modularity

[bburda]

Summary

Current src/ structure is flat and will not scale well as the project grows. We need to reorganize into a feature-based/domain-driven structure following React best practices.

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Proposed solution

Reorganize from:

src/
├── components/
│   ├── ui/           # shadcn primitives
│   └── *.tsx         # all business components mixed
├── lib/
│   ├── store.ts      # monolithic Zustand store (600+ lines)
│   ├── types.ts
│   ├── sovd-api.ts
│   └── utils.ts

To:

src/
├── components/
│   └── ui/                    # shadcn primitives only
├── features/
│   ├── connection/            # server connection dialog
│   │   ├── components/
│   │   ├── hooks/
│   │   └── store.ts
│   ├── entity-tree/           # tree sidebar & navigation
│   │   ├── components/
│   │   ├── hooks/
│   │   └── store.ts
│   ├── data/                  # topic data viewing & publishing
│   │   ├── components/
│   │   └── hooks/
│   ├── operations/            # services & actions
│   │   ├── components/
│   │   └── hooks/
│   ├── configurations/        # ROS 2 parameters
│   │   ├── components/
│   │   └── hooks/
│   └── faults/                # fault monitoring (new)
│       ├── components/
│       └── hooks/
├── hooks/                     # shared hooks
│   ├── use-debounce.ts
│   └── use-local-storage.ts
├── lib/
│   ├── api/
│   │   ├── client.ts          # base HTTP client with error handling
│   │   ├── areas.ts
│   │   ├── components.ts
│   │   ├── apps.ts
│   │   ├── operations.ts
│   │   └── types.ts
│   ├── utils.ts
│   └── constants.ts
├── theme/                     # theming, dark mode, CSS vars
│   └── index.ts
└── types/                     # shared TypeScript types
    └── index.ts

Additional context

This restructure will:

• Make codebase easier to navigate for new contributors
• Enable better code splitting and lazy loading
• Prepare for upcoming features (Apps, Functions, Faults views)