fix: Remove services/arms/ from mypy check in lint workflow

The services/arms/ directory contains no Python files yet (arms are
still in design phase), causing mypy to fail with "no .py[i] files"
error. This was preventing a clean workflow run.

Changes:
- Remove services/arms/ from mypy command in lint.yml
- Keep services/orchestrator/ which has active Python code
- mypy will continue with continue-on-error: true for type issues

This resolves the mypy directory error while maintaining code quality
checks on the implemented services.

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

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

Author: doublegate

.github/workflows/lint.yml

@@ -51,7 +51,7 @@ jobs:
       - name: Run mypy (type checking)
         run: |
           echo "Running mypy type checker..."
-          mypy services/orchestrator/ services/arms/ --ignore-missing-imports --no-error-summary
+          mypy services/orchestrator/ --ignore-missing-imports --no-error-summary
         continue-on-error: true  # Don't fail on type errors initially
 
   lint-rust: