docs: v3.9.6 - Trust Calibration, Vibe Coding Trap, reference.yaml sync

Added:
- ultimate-guide.md: Trust Calibration section (1.7) with research-backed verification strategies
- ultimate-guide.md: Infrastructure as Code Skills (Anton Babenko's terraform-skill)
- learning-with-ai.md: "The Vibe Coding Trap" anti-pattern (Karpathy, Feb 2025)
- learning-with-ai.md: "Reality of AI Productivity" section with research
- learning-with-ai.md: External resource link to leerob.com/ai (AI fundamentals)
- IDEAS.md: "Vibe Coding Discourse" watching entry

Changed:
- reference.yaml: Complete line number synchronization (~55 entries)
  Guide grew from ~9900 to 11154 lines; all deep_dive references updated
- Version bump: 3.9.5 → 3.9.6

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

README.md

@@ -276,6 +276,22 @@ Claude Code sends your prompts, file contents, and MCP results to Anthropic serv
 
 </details>
 
+<details>
+<summary><strong>Claude Cowork (for Non-Developers)</strong></summary>
+
+**Cowork** is Claude's agentic desktop feature for knowledge workers — same AI, files-only interface.
+
+| Resource | Description |
+|----------|-------------|
+| **[Cowork Documentation](./cowork/README.md)** | Complete guide hub |
+| [Getting Started](./cowork/guide/01-getting-started.md) | Setup and first workflow |
+| [Prompt Library](./cowork/prompts/) | 50+ ready-to-use prompts |
+| [Cheatsheet](./cowork/reference/cheatsheet.md) | 1-page reference |
+
+**Status**: Research preview (Pro or Max subscription, macOS only)
+
+</details>
+
 <details>
 <summary><strong>Ecosystem & Related Resources</strong></summary>
 
@@ -317,7 +333,7 @@ Licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
 
 ---
 
-*Version 3.9.5 | January 2026 | Crafted with Claude*
+*Version 3.9.6 | January 2026 | Crafted with Claude*
 
 <!-- SEO Keywords -->
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