docs: Add workspace pattern guide for serious project development (#87)

This introduces comprehensive documentation for using Amplifier with the
workspace pattern - an architectural approach where Amplifier hosts projects
as git submodules rather than projects containing Amplifier.

Changes:
- Add docs/WORKSPACE_PATTERN.md with complete guide covering:
  - Quick start for immediate setup
  - Architecture explanation with clear diagrams
  - Step-by-step setup including git submodule basics
  - AGENTS.md contract pattern for persistent AI context
  - Migration path from ai_working/ to workspace pattern
  - Working with multiple projects
  - Practical tips and troubleshooting

- Update README.md with:
  - Option 3 in QuickStart for workspace pattern setup
  - Dedicated section explaining benefits and use cases
  - Clear links to full documentation

Benefits:
- Clean version control isolation per component
- Independent Amplifier updates without affecting projects
- Persistent AI context through AGENTS.md
- Scalable to multiple simultaneous projects
- Philosophy-driven development with decision filters

This pattern is ideal for long-term projects, team collaboration, and
situations requiring clear boundaries between tool and work.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <[email protected]>

Author: bkrabach

README.md

@@ -104,6 +104,35 @@ amplifier.
 claude
 ```
 
+**Option 3** - Use the workspace pattern for serious projects
+
+For projects that need clean boundaries, independent version control, and persistent AI context:
+
+```bash
+# Fork/clone Amplifier as your workspace
+git clone https://github.com/microsoft/amplifier.git my-workspace
+cd my-workspace
+
+# Add your project as a submodule
+git submodule add <your-project-url> my-project
+
+# Set up project context (see guide for AGENTS.md template)
+cd my-project
+# Create AGENTS.md with project guidance
+
+# Start working
+cd ..
+claude
+```
+
+_In Claude Code:_
+```
+I'm working on the @my-project/ project within this workspace.
+Please read @my-project/AGENTS.md for project-specific guidance.
+```
+
+**Why use this?** Clean git history per component, independent Amplifier updates, persistent context across sessions, scalable to multiple projects. See the [Workspace Pattern Guide](docs/WORKSPACE_PATTERN.md) for full details.
+
 ---
 
 ## What Is Amplifier?
@@ -201,6 +230,27 @@ Enable with:
 - Demo-driven development patterns
 - Practical tips for effective AI-assisted development
 
+### Workspace Pattern for Serious Projects
+
+**For long-term development**, consider using the workspace pattern where Amplifier hosts your project as a git submodule. This architectural approach provides:
+
+- **Clean boundaries** - Project files stay in project directory, Amplifier stays pristine and updatable
+- **Version control isolation** - Each component maintains independent git history
+- **Context persistence** - AGENTS.md preserves project guidance across sessions
+- **Scalability** - Work on multiple projects simultaneously without interference
+- **Philosophy alignment** - Project-specific decision filters and architectural principles
+
+Perfect for:
+- Projects that will live for months or years
+- Codebases with their own git repository
+- Teams collaborating on shared projects
+- When you want to update Amplifier without affecting your projects
+- Working on multiple projects that need isolation
+
+The pattern inverts the typical relationship: instead of your project containing Amplifier, Amplifier becomes a dedicated workspace that hosts your projects. Each project gets persistent context through AGENTS.md (AI guidance), philosophy documents (decision filters), and clear namespace boundaries using `@project-name/` syntax.
+
+See the [Workspace Pattern Guide](docs/WORKSPACE_PATTERN.md) for complete setup, usage patterns, and migration from `ai_working/`.
+
 ## 🎯 Key Features
 
 ### Specialized Agents