Fix agent commands with proper content structure

- Added disable-model-invocation flag to agent commands
- Added proper task template with {{USER_MESSAGE}}
- Added detailed instructions for each command
- Updated dexto-code, dexto-database, dexto-github, dexto-pdf
- Updated prometheus-bug, prometheus-feature

This should fix "Unknown skill" errors when using these commands.

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

commands/dexto-github.md

@@ -1,8 +1,17 @@
 ---
-description: "Dexto Github Agent"
+description: "Dexto GitHub Agent - GitHub operations, PRs, issues"
+disable-model-invocation: true
 ---
 
-Use Dexto Github Agent.
+Use Dexto GitHub Agent for GitHub operations.
 
 **Task:**
 {{USER_MESSAGE}}
+
+**Instructions:**
+1. Use ~/.claude/hooks/unified-integration-v2.sh with dexto-github mode
+2. The Dexto GitHub Agent will handle:
+   - Pull request analysis
+   - Issue investigation
+   - Code review
+   - Repository management