refactor(baoyu-article-illustrator): simplify SKILL.md and add Core Styles tier

- Extract detailed workflow to references/workflow.md
- Add Core Styles for quick selection (vector, minimal-flat, sci-fi, hand-drawn, editorial, scene)
- Add vector-illustration as recommended default style
- Add Illustration Purpose (information/visualization/imagination)
- Add default composition, character rendering, text styling to prompts

skills/baoyu-article-illustrator/references/styles.md

@@ -1,10 +1,28 @@
 # Style Reference
 
+## Core Styles
+
+Simplified style tier for quick selection:
+
+| Core Style | Maps To | Best For |
+|------------|---------|----------|
+| `vector` | vector-illustration | Knowledge articles, tutorials, tech content |
+| `minimal-flat` | notion | General, knowledge sharing, SaaS |
+| `sci-fi` | blueprint | AI, frontier tech, system design |
+| `hand-drawn` | sketch/warm | Relaxed, reflective, casual content |
+| `editorial` | editorial | Processes, data, journalism |
+| `scene` | warm/watercolor | Narratives, emotional, lifestyle |
+
+Use Core Styles for most cases. See full Style Gallery below for granular control.
+
+---
+
 ## Style Gallery
 
 | Style | Description | Best For |
 |-------|-------------|----------|
-| `notion` (Default) | Minimalist hand-drawn line art | Knowledge sharing, SaaS, productivity |
+| `vector-illustration` | Clean flat vector art with bold shapes | Knowledge articles, tutorials, tech content |
+| `notion` | Minimalist hand-drawn line art | Knowledge sharing, SaaS, productivity |
 | `elegant` | Refined, sophisticated | Business, thought leadership |
 | `warm` | Friendly, approachable | Personal growth, lifestyle, education |
 | `minimal` | Ultra-clean, zen-like | Philosophy, minimalism, core concepts |
@@ -12,19 +30,31 @@
 | `watercolor` | Soft artistic with natural warmth | Lifestyle, travel, creative |
 | `editorial` | Magazine-style infographic | Tech explainers, journalism |
 | `scientific` | Academic precise diagrams | Biology, chemistry, technical research |
+| `chalkboard` | Classroom chalk drawing style | Education, teaching, explanations |
+| `fantasy-animation` | Ghibli/Disney-inspired hand-drawn | Storybook, magical, emotional |
+| `flat` | Modern bold geometric shapes | Modern digital, contemporary |
+| `flat-doodle` | Cute flat with bold outlines | Cute, friendly, approachable |
+| `intuition-machine` | Technical briefing with aged paper | Technical briefings, academic |
+| `nature` | Organic earthy illustration | Environmental, wellness |
+| `pixel-art` | Retro 8-bit gaming aesthetic | Gaming, retro tech |
+| `playful` | Whimsical pastel doodles | Fun, casual, educational |
+| `retro` | 80s/90s neon geometric | 80s/90s nostalgic, bold |
+| `sketch` | Raw pencil notebook style | Brainstorming, creative exploration |
+| `sketch-notes` | Soft hand-drawn warm notes | Educational, warm notes |
+| `vintage` | Aged parchment historical | Historical, heritage |
 
 Full specifications: `references/styles/<style>.md`
 
 ## Type × Style Compatibility Matrix
 
-| | notion | warm | minimal | blueprint | watercolor | elegant | editorial | scientific |
-|---|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
-| infographic | ✓✓ | ✓ | ✓✓ | ✓✓ | ✓ | ✓✓ | ✓✓ | ✓✓ |
-| scene | ✓ | ✓✓ | ✓ | ✗ | ✓✓ | ✓ | ✓ | ✗ |
-| flowchart | ✓✓ | ✓ | ✓ | ✓✓ | ✗ | ✓ | ✓✓ | ✓ |
-| comparison | ✓✓ | ✓ | ✓✓ | ✓ | ✓ | ✓✓ | ✓✓ | ✓ |
-| framework | ✓✓ | ✓ | ✓✓ | ✓✓ | ✗ | ✓✓ | ✓ | ✓✓ |
-| timeline | ✓✓ | ✓ | ✓ | ✓ | ✓✓ | ✓✓ | ✓✓ | ✓ |
+| | vector-illustration | notion | warm | minimal | blueprint | watercolor | elegant | editorial | scientific |
+|---|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|:---:|
+| infographic | ✓✓ | ✓✓ | ✓ | ✓✓ | ✓✓ | ✓ | ✓✓ | ✓✓ | ✓✓ |
+| scene | ✓ | ✓ | ✓✓ | ✓ | ✗ | ✓✓ | ✓ | ✓ | ✗ |
+| flowchart | ✓✓ | ✓✓ | ✓ | ✓ | ✓✓ | ✗ | ✓ | ✓✓ | ✓ |
+| comparison | ✓✓ | ✓✓ | ✓ | ✓✓ | ✓ | ✓ | ✓✓ | ✓✓ | ✓ |
+| framework | ✓✓ | ✓✓ | ✓ | ✓✓ | ✓✓ | ✗ | ✓✓ | ✓ | ✓✓ |
+| timeline | ✓ | ✓✓ | ✓ | ✓ | ✓ | ✓✓ | ✓✓ | ✓✓ | ✓ |
 
 ✓✓ = highly recommended | ✓ = compatible | ✗ = not recommended
 
@@ -32,30 +62,57 @@ Full specifications: `references/styles/<style>.md`
 
 | Type | Primary Style | Secondary Styles |
 |------|---------------|------------------|
-| infographic | blueprint | notion, editorial, scientific |
+| infographic | vector-illustration | notion, blueprint, editorial |
 | scene | warm | watercolor, elegant |
-| flowchart | notion | blueprint, editorial |
-| comparison | notion | elegant, editorial |
-| framework | blueprint | notion, scientific |
+| flowchart | vector-illustration | notion, blueprint |
+| comparison | vector-illustration | notion, elegant |
+| framework | blueprint | vector-illustration, notion |
 | timeline | elegant | warm, editorial |
 
 ## Auto Selection by Content Signals
 
 | Content Signals | Recommended Type | Recommended Style |
 |-----------------|------------------|-------------------|
-| API, metrics, data, comparison, numbers | infographic | blueprint, notion |
+| API, metrics, data, comparison, numbers | infographic | blueprint, vector-illustration |
+| Knowledge, concept, tutorial, learning, guide | infographic | vector-illustration, notion |
+| Tech, AI, programming, development, code | infographic | vector-illustration, blueprint |
+| How-to, steps, workflow, process, tutorial | flowchart | vector-illustration, notion |
+| Framework, model, architecture, principles | framework | blueprint, vector-illustration |
+| vs, pros/cons, before/after, alternatives | comparison | vector-illustration, notion |
 | Story, emotion, journey, experience, personal | scene | warm, watercolor |
-| How-to, steps, workflow, process, tutorial | flowchart | notion, minimal |
-| vs, pros/cons, before/after, alternatives | comparison | notion, elegant |
-| Framework, model, architecture, principles | framework | blueprint, notion |
 | History, timeline, progress, evolution | timeline | elegant, warm |
-| Knowledge, concept, productivity, SaaS, tool | infographic | notion |
+| Productivity, SaaS, tool, app, software | infographic | notion, vector-illustration |
 | Business, professional, strategy, corporate | framework | elegant |
 | Biology, chemistry, medical, scientific | infographic | scientific |
 | Explainer, journalism, magazine, investigation | infographic | editorial |
 
 ## Style Characteristics by Type
 
+### infographic + vector-illustration
+- Clean flat vector shapes, bold geometric forms
+- Vibrant but harmonious color palette
+- Clear visual hierarchy with icons and labels
+- Modern, professional, highly readable
+- Perfect for knowledge articles and tutorials
+
+### flowchart + vector-illustration
+- Bold arrows and connectors
+- Distinct step containers with icons
+- Clean progression flow
+- High contrast for readability
+
+### comparison + vector-illustration
+- Split layout with clear visual separation
+- Bold iconography for each side
+- Color-coded distinctions
+- Easy at-a-glance comparison
+
+### framework + vector-illustration
+- Geometric node representations
+- Clear hierarchical structure
+- Bold connecting lines
+- Modern system diagram aesthetic
+
 ### infographic + blueprint
 - Technical precision, schematic lines
 - Grid-based layout, clear zones