Add comprehensive project shortcuts system

- Create config/projects.nix for project definitions with templates
- Add scripts/templates/ with basic, content, and research workflows
- Create universal project-launcher.sh for template execution
- Integrate project system into zsh with dynamic alias generation
- Generate projects.json config file for shell script consumption
- Update README.md with project shortcuts documentation

Projects supported:
- blog: Personal blog (content workflow)
- mdshortcut: Research project (research workflow)
- nix-config: Nix configuration (basic workflow)

Usage: proj, blog, mdshortcut, nix-config commands

🤖 Generated with [Claude Code](https://claude.ai/code)

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

config/projects.nix

@@ -0,0 +1,26 @@
+{
+  projects = {
+    blog = {
+      template = "content";
+      name = "blog";
+      codePath = "/Users/yanlin/Documents/Projects/personal-blog";
+      contentPath = "/Users/yanlin/Documents/Projects/personal-blog/content";
+      description = "Personal blog project";
+    };
+    
+    mdshortcut = {
+      template = "research";
+      name = "MDShortcut";
+      codePath = "/Users/yanlin/Documents/Projects/Material Design Shortcut/MDShortcut-dev";
+      paperPath = "/Users/yanlin/Documents/Projects/Material Design Shortcut/MDShortcut-paper";
+      description = "Material Design Shortcut research project";
+    };
+    
+    nix-config = {
+      template = "basic";
+      name = "nix";
+      codePath = "/Users/yanlin/.config/nix";
+      description = "Nix configuration";
+    };
+  };
+}