feat(baoyu-xhs-images): add notebook and study-notes styles with mindmap and quadrant layouts

- notebook: hand-drawn infographic style with watercolor rendering and Morandi palette
- study-notes: realistic handwritten photo style with blue pen, red annotations, yellow highlighter
- mindmap: center radial layout (4-8 branches)
- quadrant: four-quadrant / circular section layout

skills/baoyu-xhs-images/references/presets/notebook.md

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+---
+name: notebook
+category: educational
+---
+
+# Notebook Style
+
+Hand-drawn infographic / study notes aesthetic with watercolor rendering and Morandi color palette.
+
+## Element Combination
+
+```yaml
+canvas:
+  ratio: portrait-3-4
+  grid: single | dual | triptych
+
+image_effects:
+  cutout: soft
+  stroke: none | watercolor-edge
+  filter: muted-tones | morandi
+
+typography:
+  decorated: watercolor-highlight | handwritten-bold
+  tags: pill | rounded-rect
+  direction: horizontal
+
+decorations:
+  emphasis: circle-mark | underline | checkmark
+  background: paper-texture | watercolor-wash
+  doodles: hand-drawn-lines | mindmap-nodes | speech-bubbles | hearts | peace-dove
+  frames: rounded-rect | none
+```
+
+## Color Palette (Morandi Tones)
+
+| Role | Colors | Hex |
+|------|--------|-----|
+| Primary | Sage green, Teal | #A8B5A0, #4A7C7C |
+| Background | Off-white, Warm paper | #FAF8F5, #F5F0E8 |
+| Accents | Dust blue, Warm grey, Terracotta | #8FA3B0, #9A9590, #C4A484 |
+
+## Visual Elements
+
+- Bold handwritten titles with watercolor wash blocks (sage green/teal backgrounds)
+- Black line illustrations, slightly imperfect, simulating ink effect
+- Soft paper texture background, mimicking watercolor paper
+- Mindmap nodes, list boxes, explanatory doodles
+- Symbolic icons: hearts, speech bubbles, peace dove, handshake
+- Flat lighting, vector illustration feel with analog texture
+
+## Typography
+
+- Bold handwritten fonts
+- Watercolor wash effect backgrounds
+- Clear and readable, CJK optimized
+
+## Best Layout Pairings
+
+| Layout | Compatibility | Use Case |
+|--------|---------------|----------|
+| sparse | ✓✓ | Covers, quotes |
+| balanced | ✓✓ | Standard content cards |
+| dense | ✓✓ | Knowledge cards, checklists |
+| list | ✓✓ | Step guides, rankings |
+| comparison | ✓✓ | Before/after, contrasts |
+| flow | ✓✓ | Processes, timelines |
+| mindmap | ✓✓ | Mind maps |
+| quadrant | ✓✓ | Quadrant analysis, circular sections |
+
+## Best For
+
+- Study notes, knowledge summaries
+- Mind maps, infographics
+- Tutorials, knowledge sharing
+- Bullet journal style content
+- Concept explanations, framework overviews