docs: complete Cowork documentation v1.0 (Phase 2)

- Create comprehensive Cowork docs (23 files in cowork/)
  - 6 guides: overview, getting started, capabilities, security, troubleshooting
  - 60+ ready-to-use prompts across 4 categories
  - 5 step-by-step workflows
  - Reference materials: cheatsheet, FAQ, comparison, glossary

- Integrate Perplexity research (P0/P1/P2)
  - Exact error messages with solutions (VPN, Chrome host, context limits)
  - Competitive analysis (vs Copilot/Gemini/ChatGPT/Apple Intelligence)
  - Enterprise validation (TELUS, Rakuten, Zapier stats)
  - OCR accuracy benchmarks (97% field, 63% line-item)
  - Token budget planning per task type

- Document critical limitations
  - VPN incompatibility (#1 community issue)
  - Context limit reality (165K vs 200K theoretical)
  - Platform constraints (macOS only)
  - Usage limits and pricing (Pro $20, Max $100-200)

- Update central files
  - README.md: detailed Cowork section with tables
  - VERSION: 3.9.6 → 3.9.7
  - machine-readable/reference.yaml: add cowork_reference entry
  - machine-readable/cowork-reference.yaml: new LLM-optimized index (~1.5K tokens)

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

cowork/workflows/README.md

@@ -0,0 +1,100 @@
+# Cowork Workflows
+
+> **Step-by-step tutorials for common Cowork tasks**
+
+---
+
+## Available Workflows
+
+| Workflow | Description | Time | Difficulty |
+|----------|-------------|------|------------|
+| [File Organization](file-organization.md) | Clean up messy folders | 15 min | Beginner |
+| [Expense Tracking](expense-tracking.md) | Receipts → Excel report | 20 min | Intermediate |
+| [Report Synthesis](report-synthesis.md) | Multi-doc → report | 25 min | Intermediate |
+| [Meeting Prep](meeting-prep.md) | Create briefing docs | 20 min | Intermediate |
+| [Team Handoff](team-handoff.md) | Dev ↔ Non-dev patterns | 30 min | Advanced |
+
+---
+
+## Workflow Structure
+
+Each workflow includes:
+
+1. **Use Case** — When to use this workflow
+2. **Prerequisites** — What you need before starting
+3. **Step-by-Step Instructions** — Detailed walkthrough
+4. **Example Prompts** — Copy-paste ready commands
+5. **Troubleshooting** — Common issues and solutions
+6. **Variations** — Adapting for different scenarios
+
+---
+
+## Quick Start
+
+### Before Any Workflow
+
+```bash
+# 1. Ensure workspace exists
+mkdir -p ~/Cowork-Workspace/{input,output}
+
+# 2. Backup important files
+cp -R ~/Cowork-Workspace/ ~/Cowork-Backup-$(date +%Y%m%d)/
+
+# 3. Clear previous work (optional)
+rm -rf ~/Cowork-Workspace/input/*
+rm -rf ~/Cowork-Workspace/output/*
+```
+
+### Workflow Checklist
+
+- [ ] Workspace folder ready
+- [ ] Input files in place
+- [ ] Backup if doing destructive operations
+- [ ] Cowork enabled in Claude Desktop
+- [ ] Folder access granted
+
+---
+
+## Choosing a Workflow
+
+```
+What do you need to do?
+│
+├─ Organize messy files?
+│   └─ → File Organization workflow
+│
+├─ Process receipts or expenses?
+│   └─ → Expense Tracking workflow
+│
+├─ Combine documents into a report?
+│   └─ → Report Synthesis workflow
+│
+├─ Prepare for a meeting?
+│   └─ → Meeting Prep workflow
+│
+└─ Work between technical and non-technical team members?
+    └─ → Team Handoff workflow
+```
+
+---
+
+## Tips for All Workflows
+
+### Be Explicit
+```
+❌ "Organize my files"
+✅ "Organize files in ~/Cowork-Workspace/input/ by type into subfolders"
+```
+
+### Review Before Approving
+Always read Cowork's execution plan before saying "proceed."
+
+### Start Small
+Test with a few files before processing hundreds.
+
+### Check Results
+Verify output before considering the task complete.
+
+---
+
+*[Back to Cowork Documentation](../README.md)*