feat: add Build Architecture Guard MDC directive

- Create comprehensive guard rules for build system protection
- Define protected file patterns and validation requirements
- Include risk matrix and required validation checklists
- Add emergency procedures and rollback playbooks

.cursor/rules/architecture/README.md

@@ -0,0 +1,75 @@
+# Architecture Rules Directory
+
+**Author**: Matthew Raymer
+**Date**: 2025-08-20
+**Status**: 🎯 **ACTIVE** - Architecture protection guidelines
+
+## Overview
+
+This directory contains MDC (Model Directive Configuration) rules that protect
+critical architectural components of the TimeSafari project. These rules ensure
+that changes to system architecture follow proper review, testing, and
+documentation procedures.
+
+## Available Rules
+
+### Build Architecture Guard (`build_architecture_guard.mdc`)
+
+Protects the multi-platform build system including:
+
+- Vite configuration files
+- Build scripts and automation
+- Platform-specific configurations (iOS, Android, Electron, Web)
+- Docker and deployment infrastructure
+- CI/CD pipeline components
+
+**When to use**: Any time you're modifying build scripts, configuration files,
+or deployment processes.
+
+**Authorization levels**:
+
+- **Level 1**: Minor changes (review required)
+- **Level 2**: Moderate changes (testing required)
+- **Level 3**: Major changes (ADR required)
+
+## Usage Guidelines
+
+### For Developers
+
+1. **Check the rule**: Before making architectural changes, review the relevant
+   rule
+2. **Follow the process**: Use the appropriate authorization level
+3. **Complete validation**: Run through the required checklist
+4. **Update documentation**: Keep BUILDING.md and related docs current
+
+### For Reviewers
+
+1. **Verify authorization**: Ensure changes match the required level
+2. **Check testing**: Confirm appropriate testing has been completed
+3. **Validate documentation**: Ensure BUILDING.md reflects changes
+4. **Assess risk**: Consider impact on other platforms and systems
+
+## Integration with Other Rules
+
+- **Version Control**: Works with `workflow/version_control.mdc`
+- **Research & Diagnostic**: Supports `research_diagnostic.mdc` for
+  investigations
+- **Software Development**: Aligns with development best practices
+- **Markdown Automation**: Integrates with `docs/markdown-automation.mdc` for
+  consistent documentation formatting
+
+## Emergency Procedures
+
+If architectural changes cause system failures:
+
+1. **Immediate rollback** to last known working state
+2. **Document the failure** with full error details
+3. **Investigate root cause** using diagnostic workflows
+4. **Update procedures** to prevent future failures
+
+---
+
+**Status**: Active architecture protection
+**Priority**: Critical
+**Maintainer**: Development team
+**Next Review**: 2025-09-20