Migrate tooling documentation from riddl.tech

Expands riddlc documentation with content migrated from riddl/doc:
- installation.md: Download releases or build from source
- command-reference.md: Complete command and option documentation
- configuration.md: HOCON configuration file format
- compilation.md: Compilation phases and process
- github-actions.md: CI/CD integration with get-riddlc action

Adds new sbt-riddl plugin documentation:
- Installation and configuration in sbt projects
- Integration with build workflow

Updates main riddlc index page with links to new sections.

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

Author: respencer-ncl

docs/riddl/tools/riddlc/command-reference.md

@@ -0,0 +1,220 @@
+---
+title: "Command Reference"
+description: "Complete reference for riddlc commands and options"
+---
+
+# Command Reference
+
+`riddlc` uses a subcommand structure. The general syntax is:
+
+```bash
+riddlc [common-options] command [command-options]
+```
+
+## Available Commands
+
+| Command | Description |
+|---------|-------------|
+| `about` | Print out information about RIDDL |
+| `bastify` | Convert a RIDDL file to BAST (Binary AST) format |
+| `dump` | Dump the AST of the input file |
+| `flatten` | Flatten all includes into a single file |
+| `from` | Load options from a configuration file |
+| `help` | Print usage information |
+| `info` | Print build information |
+| `onchange` | Watch a directory and run a command on changes |
+| `parse` | Parse the input file and report syntax errors |
+| `prettify` | Reformat RIDDL source to a standard layout |
+| `repeat` | Repeatedly run a command for edit-build-check cycles |
+| `stats` | Generate statistics about a RIDDL model |
+| `unbastify` | Convert a BAST file back to RIDDL source |
+| `validate` | Parse and validate the input file |
+| `version` | Print the version and exit |
+
+!!! info
+    Hugo documentation generation and diagram generation have been moved to
+    the [riddl-gen](https://github.com/ossuminc/riddl-gen) repository.
+
+## Common Options
+
+These options apply to all commands:
+
+| Option | Description |
+|--------|-------------|
+| `-t`, `--show-times` | Show parsing phase execution times |
+| `-I`, `--show-include-times` | Show parsing of included files times |
+| `-d`, `--dry-run` | Go through the motions but don't write changes |
+| `-v`, `--verbose` | Provide verbose output |
+| `-D`, `--debug` | Enable debug output (for developers) |
+| `-q`, `--quiet` | No output, just execute the command |
+| `-a`, `--no-ansi-messages` | Disable ANSI formatting in messages |
+| `-w`, `--show-warnings` | Control warning message display |
+| `-m`, `--show-missing-warnings` | Control missing definition warnings |
+| `-s`, `--show-style-warnings` | Control style warning display |
+| `-u`, `--show-usage-warnings` | Control usage warning display |
+| `-i`, `--show-info-messages` | Control info message display |
+| `-S`, `--sort-messages-by-location` | Sort messages by file and line |
+| `-G`, `--group-messages-by-kind` | Group messages by severity |
+| `-x`, `--max-parallel-parsing` | Max parallel include file parsing |
+| `--max-include-wait` | Max time to wait for include parsing |
+| `--warnings-are-fatal` | Treat warnings as errors |
+| `-B`, `--auto-generate-bast` | Auto-generate .bast files after parsing |
+
+## Command Details
+
+### parse
+
+Parse a RIDDL file for syntactic correctness without semantic validation:
+
+```bash
+riddlc parse input-file.riddl
+```
+
+This is useful for quickly checking if a file is syntactically valid.
+
+### validate
+
+Parse and semantically validate a RIDDL file:
+
+```bash
+riddlc validate input-file.riddl
+```
+
+This performs full validation including:
+
+- Reference resolution (all referenced definitions exist)
+- Type checking
+- Containment rules
+- Style checks (optional)
+
+### prettify
+
+Reformat RIDDL source to a standard layout:
+
+```bash
+riddlc prettify input-file.riddl -o output-dir
+```
+
+Options:
+
+| Option | Description |
+|--------|-------------|
+| `-o`, `--output-dir` | Required output directory |
+| `--project-name` | Project name for the output |
+| `-s`, `--single-file` | Merge all includes into a single file |
+
+### bastify
+
+Convert RIDDL to Binary AST (BAST) format for faster loading:
+
+```bash
+riddlc bastify input-file.riddl
+```
+
+Creates a `.bast` file next to the input file. BAST files can be loaded
+significantly faster than parsing RIDDL source, making them useful for
+large models.
+
+### unbastify
+
+Convert a BAST file back to RIDDL source:
+
+```bash
+riddlc unbastify input-file.bast -o output-dir
+```
+
+Options:
+
+| Option | Description |
+|--------|-------------|
+| `-o`, `--output-dir` | Output directory (default: next to input) |
+
+### flatten
+
+Resolve all includes into a single file:
+
+```bash
+riddlc flatten input-file.riddl -o output-file.riddl
+```
+
+### stats
+
+Generate statistics about a RIDDL model:
+
+```bash
+riddlc stats -I input-file.riddl
+```
+
+Reports counts of domains, contexts, entities, types, and other definitions.
+
+### from
+
+Load options from a HOCON configuration file:
+
+```bash
+riddlc from config-file.conf target-command
+```
+
+See [Configuration](configuration.md) for details on the configuration format.
+
+### repeat
+
+Support edit-build-check cycles by repeating a command:
+
+```bash
+riddlc repeat config-file.conf target-command [refresh-rate] [max-cycles]
+```
+
+Options:
+
+| Option | Description |
+|--------|-------------|
+| `refresh-rate` | How often to check for changes |
+| `max-cycles` | Maximum number of cycles |
+| `-n`, `--interactive` | Exit on EOF from stdin |
+
+### onchange
+
+Watch a directory and run a command when changes occur:
+
+```bash
+riddlc onchange config-file.conf watch-directory target-command
+```
+
+### info
+
+Display build information:
+
+```bash
+riddlc info
+```
+
+Example output:
+
+```
+[info] About riddlc:
+[info]            name: riddlc
+[info]         version: 1.1.2
+[info]   documentation: https://riddl.tech
+[info]       copyright: © 2019-2026 Ossum Inc.
+[info]        licenses: Apache License, Version 2.0
+[info]    organization: Ossum Inc.
+[info]   scala version: 3.3.7
+```
+
+### help
+
+Display usage information:
+
+```bash
+riddlc help
+riddlc help validate  # Help for specific command
+```
+
+### version
+
+Display the version number:
+
+```bash
+riddlc version
+```