Add documentation, PreCompact hook, gcal improvements, and marketplace

Documentation:
- Add commands/README.md documenting all slash commands
- Add skills/README.md documenting skill structure and patterns
- Add .claude-plugin/marketplace.json for local dev testing

Hooks:
- Add PreCompact hook to remind about context preservation
- Update hooks/README.md with new hook

GCal improvements:
- Add scripts/next_event.py for single event lookup
- Update SKILL.md with simplified format and allowed-tools: Read

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

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

commands/README.md

@@ -0,0 +1,81 @@
+# Commands
+
+Slash commands for quick actions. User-invoked (type `/command` to trigger).
+
+## Available Commands
+
+### Top-Level
+
+| Command | Aliases | Description |
+|---------|---------|-------------|
+| `/pa` | `/assistant`, `/ask` | Personal assistant entrypoint |
+| `/programmer` | | Code development tasks |
+| `/gcal` | `/calendar`, `/cal` | Google Calendar access |
+| `/usage` | `/stats` | View usage statistics |
+
+### Kubernetes (`/k8s:*`)
+
+| Command | Description |
+|---------|-------------|
+| `/k8s:cluster-status` | Quick cluster health overview |
+| `/k8s:deploy` | Deploy applications to cluster |
+| `/k8s:diagnose` | Diagnose Kubernetes issues |
+
+### System Admin (`/sysadmin:*`)
+
+| Command | Description |
+|---------|-------------|
+| `/sysadmin:health` | System health check |
+| `/sysadmin:update` | System package updates |
+| `/sysadmin:autonomy` | Set autonomy level for session |
+
+## Command Format
+
+```yaml
+---
+name: command-name
+description: What this command does
+aliases: [alias1, alias2]
+invokes: skill:skill-name    # or workflow: or agent:
+---
+
+# Command Title
+
+Instructions for Claude when command is invoked.
+```
+
+## Command vs Skill
+
+| Aspect | Command | Skill |
+|--------|---------|-------|
+| **Invocation** | User types `/command` | Claude decides automatically |
+| **Discovery** | Explicit | Based on description matching |
+| **Use case** | Quick actions, shortcuts | Domain expertise, workflows |
+
+## Directory Structure
+
+```
+commands/
+├── README.md
+├── pa.md
+├── gcal.md
+├── usage.md
+├── programmer.md
+├── k8s/
+│   ├── cluster-status.md
+│   ├── deploy.md
+│   └── diagnose.md
+└── sysadmin/
+    ├── health.md
+    ├── update.md
+    └── autonomy.md
+```
+
+Namespaced commands use subdirectories (e.g., `k8s/deploy.md` → `/k8s:deploy`).
+
+## Adding Commands
+
+1. Create `commands/name.md` (or `commands/namespace/name.md`)
+2. Add YAML frontmatter with name, description, invokes
+3. Write instructions in Markdown body
+4. Update `component-registry.json` if needed for routing