docs: add hooks example to Pattern 3 (Workflow Orchestrator)

[philoserf]

Problem

In design-patterns.md, Pattern 3 (Workflow Orchestrator) describes agents that coordinate multi-step processes, but doesn't show how hooks can enhance this pattern:

# Current example lacks hooks
name: release-coordinator
description: Coordinates the release process

Workflow orchestrators are prime candidates for hooks (logging steps, validating transitions, notifying on completion).

Solution

Expand the Pattern 3 example to include hooks:

name: release-coordinator
description: Coordinates the release process across multiple stages
model: sonnet

hooks:
  - event: "AgentStart"
    command: "./scripts/log-release-start.sh"
    description: "Log release process initiation"
  
  - event: "Bash"
    matcher:
      command: "git tag *"
    command: "./scripts/validate-tag-format.sh"
    description: "Ensure tags follow semver"
  
  - event: "AgentStop"
    command: "./scripts/notify-release-complete.sh"
    description: "Send completion notification"

focus_areas:
  - Version bumping
  - Changelog generation
  - Tag creation
  - Deployment coordination

Add a note explaining:

**Hooks in Orchestrators:** Workflow orchestrators benefit from hooks for:
- Audit logging at each stage
- Validation gates before critical operations
- Notifications on completion or failure
- Metrics collection for process optimization

Files to Update

• skills/agent-authoring/design-patterns.md

Impact

• Priority: Medium
• Effort: Medium
• User Impact: Shows hooks in a real-world architectural context

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Review context: commit f2fe29b (agent hooks documentation)