docs(tufte-press): add clear invocation instructions for users

- Add Quick Start section with simple trigger phrase examples
- Add detailed 'How to Invoke This Skill' section explaining:
  - Natural language trigger phrases
  - Conversation-based card generation
  - Detail specification (pages, depth, content preferences)
  - What the agent understands and how it responds

Makes it clear to users they just need to ask naturally:
'Create a study card about [topic]' - no special commands needed.

skills/tufte-press/README.md

@@ -2,6 +2,23 @@
 
 An AI agent skill that generates Tufte-inspired study card JSON from conversation, builds PDFs, and prints them.
 
+## Quick Start
+
+Just ask your AI agent:
+
+```
+Create a study card about [topic]
+```
+
+The agent will extract content from your conversation, generate a structured JSON study card, and optionally build a PDF and print it.
+
+**Example phrases that trigger this skill:**
+- "Create a study card about recursion"
+- "Make a printable study guide for lambda calculus"
+- "Generate a tufte-press card for this topic"
+- "Turn our conversation into a study card"
+- "Build a study card and print it duplex"
+
 ## Overview
 
 This skill provides a **complete workflow** for creating study cards:
@@ -63,6 +80,42 @@ cp -r skills/tufte-press ~/.config/opencode/skills/
 - Tectonic LaTeX compiler
 - jq for JSON validation
 
+## How to Invoke This Skill
+
+The agent automatically recognizes requests related to study cards. You don't need to explicitly mention "skill" or "tufte-press" - just describe what you want:
+
+**Trigger Phrases:**
+- "Create a study card about [topic]"
+- "Make a study guide for [concept]"
+- "Generate a tufte-press card"
+- "Turn this conversation into a study card"
+- "Build a study card and print it"
+
+**After Conversation:**
+If you've been discussing a technical topic, you can ask:
+```
+Can you create a study card from what we just discussed?
+```
+
+The agent will:
+1. Review the conversation history
+2. Extract key concepts, definitions, and examples
+3. Generate structured JSON following the tufte-press schema
+4. Optionally build PDF and/or print
+
+**Specifying Details:**
+You can guide the content:
+```
+Create a 2-page study card about dynamic programming with examples and practice problems
+```
+
+The agent understands:
+- Page count (1-3 pages)
+- Depth level (intro, intermediate, advanced)
+- Content preferences (examples, equations, practice drills)
+- Target audience
+- Print options (duplex, copies)
+
 ## Usage
 
 ### Simple Request