🔧 Standardize agent invocation syntax: @agents- → @agent-

## Changes Made
- **Agent Syntax Standardization**: Updated all agent invocations from `@agents-` to `@agent-`
- **Consistency**: Applied change across all 14 documentation files and 1 source file
- **Examples Updated**: All agent invocation examples now use singular `@agent-` format
- **Pattern Recognition**: Updated references to trigger pattern documentation

## Files Updated (14 total)
### Documentation
- Docs/User-Guide/commands.md - Core command reference
- Docs/User-Guide/agents.md - Agent guide with all examples
- Docs/README.md - Quick reference updated
- Docs/Getting-Started/installation.md & quick-start.md - Setup instructions
- Docs/Developer-Guide/ - Technical architecture and testing docs
- Docs/Reference/ - All example files and troubleshooting

### Source Files
- SuperClaude/Agents/security-engineer.md - Agent context file

## Impact
✅ **Consistent Syntax**: All agent invocations now use `@agent-[name]` format
✅ **User Clarity**: Clear distinction from previous `@agents-` plural form
✅ **Documentation Alignment**: All examples and references updated consistently
✅ **Framework Standards**: Aligns with SuperClaude naming conventions

Examples now correctly show:
- `@agent-security "review authentication"`
- `@agent-python-expert "optimize code"`
- `@agent-frontend-architect "design components"`

Total replacements: 80+ instances across entire documentation

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

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

Docs/Developer-Guide/README.md

@@ -51,7 +51,7 @@ SuperClaude is a collection of `.md` instruction files that Claude Code reads to
 **IMPORTANT**: SuperClaude is NOT a CLI tool or executable software. When you see `/sc:` commands in documentation, these are **context trigger patterns** you type in Claude Code conversations, not terminal commands.
 
 ### Agent Context Files
-Specialized instruction sets that provide domain expertise when activated by `@agents-[name]` or automatically by keywords.
+Specialized instruction sets that provide domain expertise when activated by `@agent-[name]` or automatically by keywords.
 
 ### Command Context Files
 Workflow patterns triggered by `/sc:[command]` **context patterns** (not CLI commands) that guide Claude Code through structured development tasks when you type them in Claude Code conversations.