refactor: restructure documentation into organized docs directory (#383)

- Move FAQ.md to docs/faq.md
- Create structured documentation files:
  - setup.md: Manual setup and custom GitHub app instructions
  - usage.md: Basic usage and workflow configuration
  - custom-automations.md: Automation examples
  - configuration.md: MCP servers and advanced settings
  - experimental.md: Execution modes and network restrictions
  - cloud-providers.md: AWS Bedrock and Google Vertex setup
  - capabilities-and-limitations.md: Features and constraints
  - security.md: Security information
- Condense README.md to overview with links to detailed docs
- Keep CONTRIBUTING.md, SECURITY.md, CODE_OF_CONDUCT.md at top level

docs/experimental.md

@@ -0,0 +1,106 @@
+# Experimental Features
+
+**Note:** Experimental features are considered unstable and not supported for production use. They may change or be removed at any time.
+
+## Execution Modes
+
+The action supports two execution modes, each optimized for different use cases:
+
+### Tag Mode (Default)
+
+The traditional implementation mode that responds to @claude mentions, issue assignments, or labels.
+
+- **Triggers**: `@claude` mentions, issue assignment, label application
+- **Features**: Creates tracking comments with progress checkboxes, full implementation capabilities
+- **Use case**: General-purpose code implementation and Q&A
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    # mode: tag is the default
+```
+
+### Agent Mode
+
+For automation and scheduled tasks without trigger checking.
+
+- **Triggers**: Always runs (no trigger checking)
+- **Features**: Perfect for scheduled tasks, works with `override_prompt`
+- **Use case**: Maintenance tasks, automated reporting, scheduled checks
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    mode: agent
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    override_prompt: |
+      Check for outdated dependencies and create an issue if any are found.
+```
+
+See [`examples/claude-modes.yml`](../examples/claude-modes.yml) for complete examples of each mode.
+
+## Network Restrictions
+
+For enhanced security, you can restrict Claude's network access to specific domains only. This feature is particularly useful for:
+
+- Enterprise environments with strict security policies
+- Preventing access to external services
+- Limiting Claude to only your internal APIs and services
+
+When `experimental_allowed_domains` is set, Claude can only access the domains you explicitly list. You'll need to include the appropriate provider domains based on your authentication method.
+
+### Provider-Specific Examples
+
+#### If using Anthropic API or subscription
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    # Or: claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+    experimental_allowed_domains: |
+      .anthropic.com
+```
+
+#### If using AWS Bedrock
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    use_bedrock: "true"
+    experimental_allowed_domains: |
+      bedrock.*.amazonaws.com
+      bedrock-runtime.*.amazonaws.com
+```
+
+#### If using Google Vertex AI
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    use_vertex: "true"
+    experimental_allowed_domains: |
+      *.googleapis.com
+      vertexai.googleapis.com
+```
+
+### Common GitHub Domains
+
+In addition to your provider domains, you may need to include GitHub-related domains. For GitHub.com users, common domains include:
+
+```yaml
+- uses: anthropics/claude-code-action@beta
+  with:
+    anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+    experimental_allowed_domains: |
+      .anthropic.com  # For Anthropic API
+      .github.com
+      .githubusercontent.com
+      ghcr.io
+      .blob.core.windows.net
+```
+
+For GitHub Enterprise users, replace the GitHub.com domains above with your enterprise domains (e.g., `.github.company.com`, `packages.company.com`, etc.).
+
+To determine which domains your workflow needs, you can temporarily run without restrictions and monitor the network requests, or check your GitHub Enterprise configuration for the specific services you use.