feat(agent): add devcontainer image selection

apps/agent/internal/devcontainer/README.md

@@ -0,0 +1,152 @@
+# DevContainer Package
+
+This package provides image selection logic for the Dev8 agent, enabling automatic selection of appropriate Microsoft DevContainer base images with Dev8 custom features.
+
+## Architecture
+
+The package implements a strategy for migrating from custom-built Docker images to official Microsoft DevContainer images:
+
+```
+Previous Architecture:
+┌─────────────────────────────┐
+│ dev8-ai-tools:latest        │ ← Custom 4-layer build
+│ (5-10 min build time)       │
+└─────────────────────────────┘
+
+New Architecture:
+┌─────────────────────────────┐
+│ mcr.microsoft.com/          │ ← Pre-built by Microsoft
+│ devcontainers/python:1      │   (0 build time)
+├─────────────────────────────┤
+│ + Dev8 Features (installed  │
+│   at container start):      │
+│   - supervisor              │
+│   - claude-cli              │
+│   - ai-tools                │
+└─────────────────────────────┘
+```
+
+## Components
+
+### ImageSelector
+
+Analyzes repository metadata and selects the appropriate DevContainer base image:
+
+```go
+selector := devcontainer.NewImageSelector()
+
+metadata := devcontainer.RepoMetadata{
+    Files: []string{"package.json", "tsconfig.json"},
+    PackageFiles: map[string]string{
+        "package.json": "{}",
+    },
+}
+
+spec, err := selector.SelectImage(ctx, metadata)
+// spec.BaseImage = "mcr.microsoft.com/devcontainers/typescript-node:1-20-bullseye"
+// spec.Features = [supervisor, claude-cli, ai-tools]
+```
+
+### Supported Languages
+
+The selector automatically detects and selects images for:
+
+- **TypeScript/JavaScript**: `typescript-node` image
+- **Python**: `python` image with Python 3.11
+- **Go**: `go` image with Go 1.22
+- **Rust**: `rust` image
+- **C/C++**: `cpp` image
+- **Java**: `java` image with Java 17
+- **PHP**: `php` image with PHP 8.2
+- **Universal**: Multi-language image for polyglot projects
+- **Base**: Minimal Debian image for other languages
+
+## Language Detection
+
+Language detection follows this priority:
+
+1. **Explicit language data** (from GitHub API or similar)
+2. **Package manager files**:
+   - `package.json` + `tsconfig.json` → TypeScript
+   - `package.json` → JavaScript
+   - `requirements.txt` or `pyproject.toml` → Python
+   - `go.mod` → Go
+   - `Cargo.toml` → Rust
+3. **Fallback**: Universal image
+
+## Dev8 Features
+
+All workspaces include three core features:
+
+### 1. Supervisor
+
+- Monitors workspace activity
+- Performs automated backups
+- Reports health to agent
+- Configurable via environment variables
+
+### 2. Claude CLI
+
+- Command-line interface for Anthropic's Claude
+- Supports all Claude 3 models
+- Shell completion included
+
+### 3. AI Tools Bundle
+
+- GitHub CLI with Copilot extension
+- Azure CLI for infrastructure
+- GPT and Gemini CLI wrappers
+- tmux with custom configuration
+- Productivity shell aliases
+
+## Integration with Agent
+
+The agent uses this package when creating new workspaces:
+
+```go
+// In environment service
+selector := devcontainer.NewImageSelector()
+
+// Analyze repository
+metadata := analyzeRepository(repoURL)
+
+// Select image
+spec, err := selector.SelectImage(ctx, metadata)
+
+// Deploy with selected image
+deploymentSpec := services.ContainerDeploymentSpec{
+    Image: spec.GetImageString(),
+    // ... other config
+}
+```
+
+## Benefits
+
+1. **Zero Build Time**: Microsoft images are pre-built and cached
+2. **Regular Updates**: Microsoft maintains and updates base images
+3. **Standardization**: Consistent base across all workspaces
+4. **Flexibility**: Features can be added/removed without rebuilds
+5. **Compatibility**: Works with standard DevContainer tools
+
+## Future Enhancements
+
+- [ ] Support for custom user-defined features
+- [ ] Automatic detection of framework-specific needs (Django, React, etc.)
+- [ ] Integration with existing `.devcontainer/devcontainer.json`
+- [ ] Feature version pinning per workspace
+- [ ] Dynamic feature installation based on workspace activity
+
+## Testing
+
+Run tests with:
+
+```bash
+cd apps/agent
+go test ./internal/devcontainer/...
+```
+
+## Related Documentation
+
+- [DevContainer Features](../../../packages/devcontainer-features/)
+- [Microsoft DevContainer Images](https://github.com/devcontainers/images)
+- [DevContainer Specification](https://containers.dev/)