fix: exclude venv and .venv from architecture validation

- Update .architecture-rules.yaml to ignore venv/.venv directories
- Improve _should_ignore_file() method to handle venv path exclusions
- Add explicit checks for .venv/ and venv/ in file paths

This prevents the architecture validator from scanning thousands of
files in virtual environment directories, reducing validation time
from scanning all dependency files to just project files.

Before: Scanned venv files (thousands of violations in dependencies)
After: Only scans project files (123 files checked)

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

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

.architecture-rules.yaml

@@ -399,6 +399,10 @@ ignore:
     - "**/__pycache__/**"
     - "**/migrations/**"
     - "**/node_modules/**"
+    - "**/.venv/**"
+    - "**/venv/**"
+    - ".venv/**"
+    - "venv/**"
 
   patterns:
     # Allow HTTPException in specific files