Add /diff and /template commands

- /diff command to compare config with backups
  - Shows added/removed/changed files
  - JSON-aware comparison for config files
  - List available backups
- /template command for session templates
  - Built-in templates: daily-standup, code-review, troubleshoot, deploy
  - Each template includes checklist, initial commands, prompt
  - Create custom templates interactively or non-interactively
- Updated shell completions with 21 aliases total
- Test suite now covers 29 tests

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

automation/test-scripts.sh

@@ -106,6 +106,20 @@ else
     fail "agent-info.py syntax error"
 fi
 
+# Test 13: config-diff.py
+if python3 -m py_compile "${AUTOMATION_DIR}/config-diff.py" 2>/dev/null; then
+    pass "config-diff.py syntax valid"
+else
+    fail "config-diff.py syntax error"
+fi
+
+# Test 14: session-template.py
+if python3 -m py_compile "${AUTOMATION_DIR}/session-template.py" 2>/dev/null; then
+    pass "session-template.py syntax valid"
+else
+    fail "session-template.py syntax error"
+fi
+
 echo ""
 echo "=== Skill Scripts ==="