feat: add architecture validation system with comprehensive pattern enforcement

Implemented automated architecture validation to enforce design decisions:

Architecture Validation System:
- Created .architecture-rules.yaml with comprehensive rule definitions
- Implemented validate_architecture.py script with AST-based validation
- Added pre-commit hook configuration for automatic validation
- Comprehensive documentation in docs/architecture/architecture-patterns.md

Key Design Rules Enforced:
- API-001 to API-004: API endpoint patterns (Pydantic models, no business logic, exception handling, auth)
- SVC-001 to SVC-004: Service layer patterns (domain exceptions, db session params, no HTTP concerns)
- MDL-001 to MDL-002: Model separation (SQLAlchemy vs Pydantic)
- EXC-001 to EXC-002: Exception handling (custom exceptions, no bare except)
- JS-001 to JS-003: JavaScript patterns (apiClient, logger, Alpine components)
- TPL-001: Template patterns (extend base.html)

Features:
- Validates separation of concerns (routes vs services vs models)
- Enforces proper exception handling (domain exceptions in services, HTTP in routes)
- Checks database session patterns and Pydantic model usage
- JavaScript and template validation
- Detailed error reporting with suggestions
- Integration with pre-commit hooks and CI/CD

UI Fix:
- Fixed icon names in content-pages.html (pencil→edit, trash→delete)

Documentation:
- Added architecture patterns guide with examples
- Created scripts/README.md for validator usage
- Updated mkdocs.yml with architecture documentation
- Built and verified documentation successfully

Usage:
  python scripts/validate_architecture.py              # Validate all
  python scripts/validate_architecture.py --verbose    # With details
  python scripts/validate_architecture.py --errors-only # Errors only

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

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

.pre-commit-config.yaml

@@ -0,0 +1,43 @@
+# Pre-commit hooks configuration
+# Install: pip install pre-commit
+# Setup: pre-commit install
+# Run manually: pre-commit run --all-files
+
+repos:
+  # Architecture validation
+  - repo: local
+    hooks:
+      - id: validate-architecture
+        name: Validate Architecture Patterns
+        entry: python scripts/validate_architecture.py
+        language: python
+        pass_filenames: false
+        always_run: true
+        additional_dependencies: [pyyaml]
+        verbose: true
+
+  # Python code quality
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-added-large-files
+        args: ['--maxkb=1000']
+      - id: check-json
+      - id: check-merge-conflict
+      - id: debug-statements
+
+  # Python formatting (optional - uncomment if you want)
+  # - repo: https://github.com/psf/black
+  #   rev: 23.12.1
+  #   hooks:
+  #     - id: black
+  #       language_version: python3
+
+  # Python import sorting (optional)
+  # - repo: https://github.com/pycqa/isort
+  #   rev: 5.13.2
+  #   hooks:
+  #     - id: isort