Add project documentation and beads configuration

- Added CLAUDE.md with project overview and architecture details
- Added PRD.md with product requirements
- Added AGENTS.md for agent workflow documentation
- Initialized beads issue tracking system
- Added .gitattributes for Git configuration

CLAUDE.md

@@ -0,0 +1,102 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+A Go library for the Bookstack REST API. Primary consumers are AI agents via CLI (with `--json` flag) and Go developers needing programmatic Bookstack access.
+
+## Build & Test Commands
+
+```bash
+# Build
+go build ./...
+
+# Run all tests
+go test ./...
+
+# Run single test
+go test -run TestName ./...
+
+# Run tests with coverage
+go test -cover ./...
+
+# Lint (if golangci-lint is installed)
+golangci-lint run
+
+# Format code
+gofmt -w .
+```
+
+## Architecture
+
+### Flat Package Structure
+
+All code lives in the root package `bookstack`. No subpackages.
+
+```
+bookstack.go       # Client, Config, NewClient()
+books.go           # BooksService
+pages.go           # PagesService
+chapters.go        # ChaptersService
+shelves.go         # ShelvesService
+search.go          # SearchService
+types.go           # All data structures (Book, Page, Chapter, Shelf, SearchResult)
+errors.go          # Error types (ErrNotFound, ErrUnauthorized, APIError, etc.)
+http.go            # HTTP helpers, request building
+iterator.go        # Pagination iterator using Go 1.23+ iter.Seq
+```
+
+### Client Pattern
+
+Services are attached to the main `Client` struct:
+
+```go
+client := bookstack.NewClient(bookstack.Config{
+    BaseURL:     "https://docs.example.com",
+    TokenID:     os.Getenv("BOOKSTACK_TOKEN_ID"),
+    TokenSecret: os.Getenv("BOOKSTACK_TOKEN_SECRET"),
+})
+
+// Access services via client
+books, err := client.Books.List(ctx, nil)
+page, err := client.Pages.Get(ctx, 123)
+```
+
+### Pagination via Iterators
+
+Use Go 1.23+ iterator pattern for list operations:
+
+```go
+for book, err := range client.Books.ListAll(ctx) {
+    if err != nil {
+        return err
+    }
+    // process book
+}
+```
+
+### Error Handling
+
+Use sentinel errors with `errors.Is()`:
+
+```go
+if errors.Is(err, bookstack.ErrNotFound) {
+    // handle 404
+}
+```
+
+`APIError` provides detailed information when needed.
+
+## Key Design Decisions
+
+- **Zero external dependencies** - Only Go standard library
+- **Go 1.21+** required
+- **No caching/rate-limiting** - Caller responsibility
+- **Token auth** via `Authorization: Token <id>:<secret>` header
+- **Bookstack hierarchy**: Shelf → Book → Chapter → Page
+
+## Bookstack API Reference
+
+- Rate limit: 180 req/min (server configurable)
+- Pagination: `count` (max 500), `offset`, `sort`, `filter[field]`