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>

machine-readable/reference.yaml

@@ -3,8 +3,8 @@
 # Source: guide/ultimate-guide.md
 # Purpose: Condensed index for LLMs to quickly answer user questions about Claude Code
 
-version: "3.9.6"
-updated: "2026-01"
+version: "3.9.7"
+updated: "2026-01-20"
 
 # ════════════════════════════════════════════════════════════════
 # DEEP DIVE - Line numbers in guide/ultimate-guide.md
@@ -119,7 +119,8 @@ deep_dive:
   ai_ecosystem_voice_to_text: "guide/ai-ecosystem.md:449"
   ai_ecosystem_alternative_providers: "guide/ai-ecosystem.md:959"
   voice_refine_skill: "examples/skills/voice-refine/SKILL.md"
-  # Cowork documentation (expanded - see cowork/)
+  # Cowork documentation (v1.0 - complete)
+  cowork_reference: "machine-readable/cowork-reference.yaml"  # Dedicated YAML index
   cowork_hub: "cowork/README.md"
   cowork_summary: "guide/cowork.md"
   cowork_overview: "cowork/guide/00-overview.md"