docs: add Obsidian skills usage guide

Added comprehensive guide for Obsidian visualization skills:

**Installed Obsidian Skills:**
1. obsidian-bases - Database view management
2. obsidian-cli - Command-line operations
3. obsidian-markdown - Flavored markdown creation

**Installed Obsidian Plugins:**
Community Plugins:
- dataview - Query and visualize data
- kanban - Task board view
- calendar - Daily notes calendar
- heatmap - Activity heatmap (GitHub-style)
- obsidian-tasks-plugin - Advanced task management
- obsidian-chart - Create charts and graphs
- obsidian-advanced-slides - Presentation slides
- obsidian-git - Git version control

Core Plugins:
- canvas - Whiteboard canvas
- bases - Database views
- graph - Relationship graph
- graph-analysis - Graph analysis
- webviewer - Web content viewer

**Guide Contents:**
- Skill usage examples
- Visualization workflows
- Best practices
- Keyboard shortcuts
- Troubleshooting tips
- Integration with Claude Code

**Use Cases:**
1. Knowledge graph building with Graph + Canvas
2. Learning progress tracking with Kanban + Tasks
3. Interview preparation planning with Bases
4. Statistics visualization with Charts
5. Daily learning flow with Calendar + Heatmap

All configurations saved in .obsidian/ for automatic sync.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

.obsidian/workspace.json

@@ -196,6 +196,7 @@
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