chore: initial project setup with agent guide

.agent/skills/gsd-update/SKILL.md

@@ -0,0 +1,35 @@
+---
+name: gsd-update
+description: Update GSD to latest version with changelog display
+---
+
+
+<objective>
+Check for GSD updates, install if available, and display what changed.
+
+Routes to the update workflow which handles:
+- Version detection (local vs global installation)
+- npm version checking
+- Changelog fetching and display
+- User confirmation with clean install warning
+- Update execution and cache clearing
+- Restart reminder
+</objective>
+
+<execution_context>
+@.agent/get-shit-done/workflows/update.md
+</execution_context>
+
+<process>
+**Follow the update workflow** from `@.agent/get-shit-done/workflows/update.md`.
+
+The workflow handles all logic including:
+1. Installed version detection (local/global)
+2. Latest version checking via npm
+3. Version comparison
+4. Changelog fetching and extraction
+5. Clean install warning display
+6. User confirmation
+7. Update execution
+8. Cache clearing
+</process>