Add project documentation overview and structure

Introduces a new instructions markdown file detailing the documentation management system's architecture, including client library, API server, and web studio interface. Provides directory structure and descriptions for key components to aid onboarding and development.

Author: shigurenimo

.github/instructions/~.instructions.md

@@ -0,0 +1,67 @@
+---
+applyTo: "**"
+---
+
+# Overview
+
+Documentation management system with client library, API server, and web studio interface.
+
+## Directory Structure
+
+### Root
+- `mcp.ts` - MCP (Model Context Protocol) implementation
+- `index.dev.ts` - Development entry point
+- `init.ts` - Initialization script
+
+### packages/
+
+#### docs-client/
+Documentation client library for file management and processing
+
+- `lib/` - Core library
+  - `entities/` - Document entities (file, index, markdown)
+    - `doc-file-entity.ts` - Base file entity
+    - `doc-file-index-entity.ts` - Index file entity
+    - `doc-file-md-entity.ts` - Markdown file entity
+    - `doc-file-unknown-entity.ts` - Unknown file type entity
+  - `values/` - Value objects
+    - `doc-custom-schema-field/` - Custom field implementations
+    - `doc-meta-field/` - Meta field implementations
+    - `doc-schema-field/` - Schema field implementations
+    - Tree and path value objects
+  - `doc-client.ts` - Main client API
+  - `doc-file-system.ts` - File system operations
+  - `doc-markdown-system.ts` - Markdown processing
+  - `doc-schema-builder.ts` - Schema construction
+  - Reference implementations for directories and files
+
+#### docs-router/
+API server using Hono framework
+
+- `lib/` - Server implementation
+  - `routes/` - API endpoints
+    - `directories.$path.ts` - Directory operations
+    - `directories.tree.ts` - Directory tree operations
+    - `files.$path.ts` - File operations
+    - `files.ts` - File listing
+  - `utils/` - Server utilities
+    - `cwd.ts` - Working directory utilities
+    - `factory.ts` - Handler factory
+  - `client.ts` - API client
+  - `env.ts` - Environment configuration
+- `server.ts` - Server entry point
+
+#### docs-studio/
+React-based web interface
+
+- `app/` - React application
+  - `components/` - UI components
+    - `ui/` - Base UI components (shadcn/ui)
+    - `file-view/` - File viewing/editing components
+    - `project-view/` - Project management views
+    - `editable-table-cell/` - Table cell editors
+  - `hooks/` - Custom React hooks
+  - `routes/` - TanStack Router routes
+  - `lib/` - Frontend utilities
+    - `open-csv/` - CSV processing
+    - `api-client.ts` - API client wrapper