docs: add mdBook-based documentation with GitHub Pages deployment

Add comprehensive documentation as an mdBook covering installation, features, customization, examples, and reference materials. Include GitHub Actions workflow for automatic deployment to GitHub Pages on push to master.

Author: pamburus

.github/workflows/book-deploy.yml

@@ -0,0 +1,38 @@
+name: Book
+
+on:
+  push:
+    branches: ["feature/book"]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - name: Set up mdBook
+        uses: peaceiris/actions-mdbook@ee69d230fe19748b7abf22df32acaa93833fad08 # v2.0.0
+        with:
+          mdbook-version: "0.5.2"
+
+      - name: Build Book
+        run: mdbook build docs
+
+      - name: Setup Pages
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
+
+      - name: Upload Artifact
+        uses: actions/upload-pages-artifact@7b1f4a764d45c48632c6b24a0339c27f5614fb0b # v4.0.0
+        with:
+          path: "./docs/book"
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5

README.md

@@ -1,4 +1,4 @@
-# hl [![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov] [![Release][release-img]][release]
+# hl [![Book][book-img]][book] [![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov] [![Release][release-img]][release]
 
 [![banner](docs/assets/banner.svg)](#screenshot)
 
@@ -871,6 +871,8 @@ Advanced Options:
 
   * See [#132](https://github.com/pamburus/hl/issues/132) for how to repeat measurements
 
+[book-img]: https://github.com/pamburus/hl/actions/workflows/book.yml/badge.svg?branch=feature/book
+[book]: https://pamburus.github.io/hl/
 [ci-img]: https://github.com/pamburus/hl/actions/workflows/ci.yml/badge.svg
 [ci]: https://github.com/pamburus/hl/actions/workflows/ci.yml
 [cov-img]: https://codecov.io/gh/pamburus/hl/graph/badge.svg?token=464MN13408

docs/.gitignore

@@ -0,0 +1 @@
+/book/

docs/book.toml

@@ -0,0 +1,9 @@
+[book]
+authors = ["hl contributors"]
+language = "en"
+src = "src"
+title = "hl - Log Viewer Guide"
+description = "Complete guide to using hl, a high-performance JSON and logfmt log viewer"
+
+[output.html]
+git-repository-url = "https://github.com/pamburus/hl"

docs/src/SUMMARY.md

@@ -0,0 +1,69 @@
+# Summary
+
+[Introduction](./intro.md)
+
+# Getting Started
+
+- [Installation](./installation.md)
+- [Quick Start](./quick-start.md)
+
+# Features
+
+- [Viewing Logs](./features/viewing-logs.md)
+  - [Automatic Pager Integration](./features/pager.md)
+  - [Live Streaming](./features/streaming.md)
+  - [Multiple Files](./features/multiple-files.md)
+  - [Compressed Files](./features/compressed.md)
+
+- [Filtering](./features/filtering.md)
+  - [By Log Level](./features/filtering-level.md)
+  - [By Field Values](./features/filtering-fields.md)
+  - [By Time Range](./features/filtering-time.md)
+  - [Complex Queries](./features/filtering-queries.md)
+
+- [Sorting and Following](./features/sorting.md)
+  - [Follow Mode](./features/follow-mode.md)
+
+- [Output Formatting](./features/formatting.md)
+  - [Field Visibility](./features/field-visibility.md)
+  - [Time Display](./features/time-display.md)
+  - [Field Expansion](./features/field-expansion.md)
+  - [Raw Output](./features/raw-output.md)
+
+- [Input Options](./features/input.md)
+  - [Input Formats](./features/input-formats.md)
+  - [Time Handling Overview](./features/time-handling-overview.md)
+  - [Timestamp Handling](./features/timestamps.md)
+  - [Non-JSON Prefixes](./features/prefixes.md)
+
+# Customization
+
+- [Configuration Files](./customization/config-files.md)
+- [Environment Variables](./customization/environment.md)
+- [Themes](./customization/themes.md)
+  - [Stock Themes](./customization/themes-stock.md)
+  - [Selecting Themes](./customization/themes-selecting.md)
+  - [Custom Themes](./customization/themes-custom.md)
+  - [Theme Overlays](./customization/themes-overlays.md)
+
+# Examples
+
+- [Basic Usage](./examples/basic.md)
+- [Filtering Examples](./examples/filtering.md)
+- [Query Examples](./examples/queries.md)
+- [Time Filtering](./examples/time-filtering.md)
+- [Field Management](./examples/field-management.md)
+- [Live Monitoring](./examples/live-monitoring.md)
+- [Working with Multiple Logs](./examples/multiple-logs.md)
+
+# Reference
+
+- [Command-Line Options](./reference/options.md)
+- [Query Syntax](./reference/query-syntax.md)
+- [Time Format Specifications](./reference/time-format.md)
+- [Performance Tips](./reference/performance.md)
+
+# Help
+
+- [Troubleshooting](./help/troubleshooting.md)
+- [FAQ](./help/faq.md)