Implement /gcal Google Calendar integration

Components:
- commands/gcal.md: Slash command with aliases (calendar, cal)
- skills/gcal/SKILL.md: Usage patterns, routing logic, output formats
- mcp/delegation/gcal_delegate.py: Python API wrapper with tiered delegation

Features:
- Subcommands: today, tomorrow, week, next, summary
- Smart default (today before 6pm, tomorrow after)
- Hybrid interface (subcommands + natural language)
- Haiku tier for fetch/format, Sonnet tier for analysis

Requires OAuth setup: enable Calendar API and authorize.

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

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

commands/gcal.md

@@ -0,0 +1,39 @@
+---
+name: gcal
+description: Google Calendar agenda overview and smart summaries
+aliases: [calendar, cal]
+invokes: skill:gcal
+---
+
+# /gcal Command
+
+Google Calendar access for agenda overview and event details.
+
+## Usage
+
+```
+/gcal                   # Smart default (today before 6pm, tomorrow after)
+/gcal today             # Today's agenda
+/gcal tomorrow          # Tomorrow's agenda
+/gcal week              # Next 7 days, grouped by day
+/gcal next              # Next upcoming event
+/gcal summary           # Sonnet-powered week analysis
+/gcal <natural>         # Natural language (e.g., "what's on Friday?")
+```
+
+## Examples
+
+```
+/gcal                   # What's on my calendar?
+/gcal today             # Show today's events
+/gcal week              # Show this week
+/gcal summary           # Analyze my week
+/gcal am I free Tuesday # Natural language query
+```
+
+## Delegation Tiers
+
+| Subcommand | Tier | Reason |
+|------------|------|--------|
+| today, tomorrow, week, next | Haiku | Fetch + format only |
+| summary | Sonnet | Requires analysis |