docs: rewrite README to describe ConceptSketch project (closes #4)

Reviewed-on: #3

README.md

@@ -1,73 +1,70 @@
-# React + TypeScript + Vite
+# ConceptSketch
 
-This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+An interactive concept map editor for creating and exploring hierarchical graph diagrams. Build knowledge structures visually by connecting nodes into nested subgraphs.
 
-Currently, two official plugins are available:
+## Features
 
-- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Babel](https://babeljs.io/) (or [oxc](https://oxc.rs) when used in [rolldown-vite](https://vite.dev/guide/rolldown)) for Fast Refresh
+- **Interactive graph editing** — click nodes to create children, ctrl+click to multi-select, click edges to remove them
-- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
+- **Nested subgraphs** — convert any node into its own subgraph layer for infinite nesting
+- **Breadcrumb navigation** — navigate through graph hierarchy with breadcrumb trail
+- **Sidebar tree view** — see and navigate the full hierarchical structure at a glance
+- **Rename nodes** — right-click any node to rename, create subgraphs, or remove
+- **Orphaned nodes** — right-click empty canvas area to create standalone nodes
+- **Save & load** — export/import your entire graph as a JSON file
 
-## React Compiler
+## Getting Started
 
-The React Compiler is not enabled on this template because of its impact on dev & build performances. To add it, see [this documentation](https://react.dev/learn/react-compiler/installation).
+### Prerequisites
 
-## Expanding the ESLint configuration
+- Node.js (v18+)
+- npm
 
-If you are developing a production application, we recommend updating the configuration to enable type-aware lint rules:
+### Installation
 
-```js
+```bash
-export default defineConfig([
+npm install
-  globalIgnores(['dist']),
-  {
-    files: ['**/*.{ts,tsx}'],
-    extends: [
-      // Other configs...
-
-      // Remove tseslint.configs.recommended and replace with this
-      tseslint.configs.recommendedTypeChecked,
-      // Alternatively, use this for stricter rules
-      tseslint.configs.strictTypeChecked,
-      // Optionally, add this for stylistic rules
-      tseslint.configs.stylisticTypeChecked,
-
-      // Other configs...
-    ],
-    languageOptions: {
-      parserOptions: {
-        project: ['./tsconfig.node.json', './tsconfig.app.json'],
-        tsconfigRootDir: import.meta.dirname,
-      },
-      // other options...
-    },
-  },
-])
 ```
 
-You can also install [eslint-plugin-react-x](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x) and [eslint-plugin-react-dom](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-dom) for React-specific lint rules:
+### Development
 
-```js
+```bash
-// eslint.config.js
+npm run dev
-import reactX from 'eslint-plugin-react-x'
-import reactDom from 'eslint-plugin-react-dom'
-
-export default defineConfig([
-  globalIgnores(['dist']),
-  {
-    files: ['**/*.{ts,tsx}'],
-    extends: [
-      // Other configs...
-      // Enable lint rules for React
-      reactX.configs['recommended-typescript'],
-      // Enable lint rules for React DOM
-      reactDom.configs.recommended,
-    ],
-    languageOptions: {
-      parserOptions: {
-        project: ['./tsconfig.node.json', './tsconfig.app.json'],
-        tsconfigRootDir: import.meta.dirname,
-      },
-      // other options...
-    },
-  },
-])
 ```
+
+Opens at `http://localhost:5173` with hot module replacement.
+
+### Build
+
+```bash
+npm run build
+```
+
+### Tests
+
+```bash
+npx playwright test
+```
+
+## Usage
+
+| Action | Result |
+|---|---|
+| Click a node | Create a new child node |
+| Ctrl+click nodes, then click target | Link selected nodes as parents to target |
+| Click an edge | Delete that edge |
+| Right-click a node | Open context menu (Rename / Subgraph / Remove) |
+| Right-click empty area | Create an orphaned (unconnected) node |
+| Click sidebar tree item | Navigate to that subgraph |
+
+## Tech Stack
+
+- **React 19** + **TypeScript**
+- **Vite** — build tool
+- **Viz.js** (Graphviz) — graph rendering
+- **D3** — SVG interactivity
+- **Ant Design** — UI components
+- **Zustand** — state management
+
+## File Format
+
+Graphs are saved as `concept-sketch.json`. The format supports nested subgraphs with recursive structure, preserving the full hierarchy.

src/components/Graph.tsx

@@ -264,12 +264,7 @@ const Graph = forwardRef<GraphHandle, { setGraphPath: React.Dispatch<React.SetSt
       title: selectedNodeName,
       key: pathSegmentId,
       onClick: () => {
-        const index = graphsPath.findIndex(p => p.key === pathSegmentId);
+        setGraphsPath(prev => prev.slice(0, prev.findIndex(p => p.key === pathSegmentId) + 1));
-        setGraphsPath(prev => {
-          prev.splice(index + 1);
-
-          return [...prev];
-        });
         selectGraphId(pathSegmentId);
       }
     } as BreadcrumbItemType;