feat: Add headless configuration (#37)

## Summary

This PR adds headless browser configuration support and updates project
dependencies to their latest versions.

### Key Changes

**Browser Configuration:**
- ✅ Add `BROWSER_HEADLESS` environment variable support (default:
`true`)
- ✅ Fix hardcoded headless value in `NewBrowserConfigFromConfig`
function (internal/playwright/playwright.go:92)
- ✅ Allow users to disable headless mode for debugging and development
by setting `BROWSER_HEADLESS=false`
- ✅ Update README with `BROWSER_HEADLESS` configuration documentation

**Dependency Updates:**
- ✅ Upgrade ADL CLI from v0.23.7 to v0.23.8 in generated workflow and
configuration files
- ✅ Upgrade ADK dependency from v0.15.1 to v0.15.2 in go.mod
- ✅ Upgrade Claude Code from 2.0.11 to 2.0.15 in Flox manifest

**Refactoring:**
- ✅ Streamline artifact server creation in main.go

### Configuration Usage

Users can now control headless mode via environment variable:

```bash
# Run in headless mode (default)
BROWSER_HEADLESS=true go run .

# Run with visible browser for debugging
BROWSER_HEADLESS=false go run .
```

### Testing

- ✅ All unit tests pass
- ✅ Linter checks pass (0 issues)
- ✅ Headless configuration properly reads from environment

### Files Changed

- `agent.yaml` - Added headless configuration
- `config/config.go` - Added Headless field to BrowserConfig struct
- `internal/playwright/playwright.go` - Fixed hardcoded headless value
to use config
- `README.md` - Documented BROWSER_HEADLESS variable
- `main.go` - Refactored artifact server creation
- `.flox/env/manifest.toml` - Updated Claude Code version
- `.github/workflows/ci.yml` - Updated ADL CLI version
- `go.mod` / `go.sum` - Updated ADK dependency

---

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

---------

Signed-off-by: Eden Reich <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: edenreich

.flox/env/manifest.lock

@@ -22,7 +22,7 @@ docker.pkg-group = "common"
 
 claude-code.pkg-path = "claude-code"
 claude-code.pkg-group = "common"
-claude-code.version = "2.0.11"
+claude-code.version = "2.0.15"
 
 [hook]
 on-activate = '''

.flox/env/manifest.toml

@@ -10,7 +10,7 @@ browser-agent is an A2A (Agent-to-Agent) server implementing the [A2A Protocol](
 
 ### ADL-Generated Structure
 
-The codebase is generated using ADL CLI 0.23.7 and follows a strict generation pattern:
+The codebase is generated using ADL CLI 0.23.8 and follows a strict generation pattern:
 - **Generated Files**: Marked with `DO NOT EDIT` headers - manual changes will be overwritten
 - **Configuration Source**: `agent.yaml` - defines agent capabilities, skills, and metadata
 - **Server Implementation**: Built on the ADK (Agent Development Kit) framework from `github.com/inference-gateway/adk`
@@ -117,7 +117,7 @@ Activate with: `flox activate` (if Flox is installed)
 
 - **Generated Files**: Never manually edit files with "DO NOT EDIT" headers
 - **Configuration Changes**: Always modify `agent.yaml` and regenerate
-- **ADL Version**: Ensure ADL CLI 0.23.7 or compatible version for regeneration
+- **ADL Version**: Ensure ADL CLI 0.23.8 or compatible version for regeneration
 - **Port Configuration**: Default 8080, configurable via `A2A_PORT` or `A2A_SERVER_PORT`
 
 ## Debugging Tips

.github/workflows/cd.yml

@@ -68,6 +68,7 @@ The following custom configuration variables are available:
 | **Browser** | `BROWSER_HEADER_CONNECTION` | Header_connection configuration | `keep-alive` |
 | **Browser** | `BROWSER_HEADER_DNT` | Header_dnt configuration | `1` |
 | **Browser** | `BROWSER_HEADER_UPGRADE_INSECURE_REQUESTS` | Header_upgrade_insecure_requests configuration | `1` |
+| **Browser** | `BROWSER_HEADLESS` | Headless configuration | `true` |
 | **Browser** | `BROWSER_USER_AGENT` | User_agent configuration | `Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36` |
 | **Browser** | `BROWSER_VIEWPORT_HEIGHT` | Viewport_height configuration | `1080` |
 | **Browser** | `BROWSER_VIEWPORT_WIDTH` | Viewport_width configuration | `1920` |

.github/workflows/ci.yml

@@ -11,6 +11,7 @@ spec:
     stateTransitionHistory: false
   config:
     browser:
+      headless: true
       user_agent: "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
       viewport_width: 1920
       viewport_height: 1080