docs: add comprehensive user documentation

Added documentation covering all ghx-cli features:

- docs/README.md: Documentation index
- docs/getting-started.md: Installation and quick start guide
- docs/configuration.md: Configuration options
- docs/troubleshooting.md: Common issues and solutions
- docs/examples.md: Cookbook with workflows and scripts

Command references:
- docs/commands/README.md: Command overview
- docs/commands/project.md: Project management
- docs/commands/item.md: Item management
- docs/commands/field.md: Field management
- docs/commands/view.md: View management
- docs/commands/discussion.md: Discussion management
- docs/commands/analytics.md: Analytics and bulk operations
- docs/commands/auth.md: Authentication

Partially addresses #15

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: serithemage

docs/README.md

@@ -0,0 +1,48 @@
+# ghx-cli Documentation
+
+Welcome to the ghx-cli documentation. This guide covers all features and commands of the GitHub eXtensions CLI.
+
+## Table of Contents
+
+### Getting Started
+- [Installation & Quick Start](getting-started.md) - Install ghx-cli and run your first commands
+
+### Command Reference
+- [Command Overview](commands/README.md) - All available commands at a glance
+- [project](commands/project.md) - Manage GitHub Projects v2
+- [item](commands/item.md) - Manage project items (issues, PRs, drafts)
+- [field](commands/field.md) - Manage custom fields
+- [view](commands/view.md) - Manage project views (table, board, roadmap)
+- [discussion](commands/discussion.md) - Manage GitHub Discussions
+- [analytics](commands/analytics.md) - Generate reports and bulk operations
+- [auth](commands/auth.md) - Manage authentication
+
+### Guides
+- [Configuration](configuration.md) - Configure ghx-cli settings
+- [Examples & Cookbook](examples.md) - Common use cases and workflows
+- [Troubleshooting](troubleshooting.md) - Common issues and solutions
+
+### Reference
+- [Feature Comparison](feature-comparison.md) - ghx-cli vs gh CLI capabilities
+- [PRD](PRD.md) - Product Requirements Document
+
+## Quick Links
+
+```bash
+# Check authentication status
+ghx auth status
+
+# List your projects
+ghx project list
+
+# List discussions in a repository
+ghx discussion list owner/repo
+
+# Get help for any command
+ghx [command] --help
+```
+
+## Support
+
+- [GitHub Issues](https://github.com/roboco-io/ghx-cli/issues) - Report bugs and request features
+- [GitHub Discussions](https://github.com/roboco-io/ghx-cli/discussions) - Ask questions and share ideas

docs/commands/README.md

@@ -0,0 +1,118 @@
+# Command Reference
+
+ghx-cli provides commands organized into logical groups for managing GitHub Projects and Discussions.
+
+## Command Groups
+
+| Command | Description |
+|---------|-------------|
+| [ghx project](project.md) | Manage GitHub Projects v2 |
+| [ghx item](item.md) | Manage project items (issues, PRs, drafts) |
+| [ghx field](field.md) | Manage custom fields |
+| [ghx view](view.md) | Manage project views |
+| [ghx discussion](discussion.md) | Manage GitHub Discussions |
+| [ghx analytics](analytics.md) | Generate reports and bulk operations |
+| [ghx auth](auth.md) | Manage authentication |
+
+## Global Flags
+
+These flags are available for all commands:
+
+| Flag | Description | Default |
+|------|-------------|---------|
+| `--config` | Config file path | `$HOME/.ghx.yaml` |
+| `--token` | GitHub Personal Access Token | - |
+| `--org` | GitHub organization | - |
+| `--user` | GitHub user | - |
+| `--format` | Output format (table, json, yaml) | `table` |
+| `--debug` | Enable debug output | `false` |
+| `--no-cache` | Disable caching | `false` |
+| `-h, --help` | Help for command | - |
+| `-v, --version` | Version information | - |
+
+## Command Structure
+
+Commands follow this pattern:
+
+```
+ghx <group> <action> [arguments] [flags]
+```
+
+Examples:
+```bash
+ghx project list                    # List projects
+ghx project view myorg/123          # View specific project
+ghx item add myorg/123 repo#42      # Add item to project
+ghx discussion create owner/repo    # Create discussion
+```
+
+## Output Formats
+
+### Table (Default)
+
+Human-readable table format:
+
+```bash
+ghx project list
+```
+
+```
+NUMBER  TITLE           ITEMS  UPDATED
+1       Sprint 1        42     2024-01-15
+2       Backlog         128    2024-01-14
+```
+
+### JSON
+
+Machine-readable JSON format:
+
+```bash
+ghx project list --format json
+```
+
+```json
+[
+  {"number": 1, "title": "Sprint 1", "items": 42},
+  {"number": 2, "title": "Backlog", "items": 128}
+]
+```
+
+### YAML
+
+YAML format for configuration files:
+
+```bash
+ghx project list --format yaml
+```
+
+```yaml
+- number: 1
+  title: Sprint 1
+  items: 42
+- number: 2
+  title: Backlog
+  items: 128
+```
+
+## Exit Codes
+
+| Code | Meaning |
+|------|---------|
+| 0 | Success |
+| 1 | General error |
+| 2 | Invalid arguments |
+| 3 | Authentication error |
+| 4 | API error |
+
+## Getting Help
+
+```bash
+# General help
+ghx --help
+
+# Group help
+ghx project --help
+
+# Command help
+ghx project create --help
+```