Add plugin manifest and documentation for agents/workflows

- Add .claude-plugin/plugin.json for potential plugin distribution
- Add agents/README.md explaining agent file purpose and usage
- Add workflows/README.md clarifying that workflows are design docs,
  not executable automation (Claude Code doesn't natively execute YAML)

This improves documentation and enables potential future portability
as a plugin.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

agents/README.md

@@ -0,0 +1,63 @@
+# Agent Definitions
+
+This directory contains agent persona definitions for the multi-agent system.
+
+## Purpose
+
+Agent files define specialized personas that Claude can adopt when working on specific domains. They are:
+
+- **Persona documents** - Define behavior, responsibilities, and constraints
+- **Reference material** - Loaded into context when the domain is relevant
+- **Subagent templates** - Can be spawned via Task tool with explicit prompting
+
+## Active Agents
+
+| Agent | Model | Domain |
+|-------|-------|--------|
+| `personal-assistant` | Opus | User interface, top-level oversight |
+| `master-orchestrator` | Opus | Cross-agent coordination, policy enforcement |
+| `linux-sysadmin` | Sonnet | Workstation management |
+| `k8s-orchestrator` | Opus | Kubernetes cluster management |
+| `programmer-orchestrator` | Opus | Code development coordination |
+
+## Supporting Agents (K8s)
+
+| Agent | Model | Domain |
+|-------|-------|--------|
+| `k8s-diagnostician` | Sonnet | Cluster health, pod diagnostics |
+| `argocd-operator` | Sonnet | GitOps deployments |
+| `prometheus-analyst` | Sonnet | Metrics and alerting |
+| `git-operator` | Sonnet | Repository operations |
+
+## Supporting Agents (Programming)
+
+| Agent | Model | Domain |
+|-------|-------|--------|
+| `code-planner` | Sonnet | Design and architecture |
+| `code-implementer` | Sonnet | Code writing |
+| `code-reviewer` | Sonnet | Code review and quality |
+
+## Agent File Format
+
+```yaml
+---
+name: agent-name
+description: When to use this agent
+model: sonnet|opus|haiku
+tools: Tool1, Tool2, ...
+---
+
+# Agent Name
+
+[Instructions in Markdown]
+```
+
+## Note on Execution
+
+Claude Code doesn't automatically spawn agents from this hierarchy. To use an agent:
+
+1. **Skill-based activation** - If a skill description matches, Claude uses that context
+2. **Explicit Task tool** - Use Task tool with agent prompt to spawn subagent
+3. **Manual prompt** - Reference agent file directly
+
+The hierarchy is primarily for organization and documentation.