Test improvements and fixes
- test-chat.cpp: Add expect_tool_ids flag for templates that don't generate tool IDs
- test-chat.cpp: Remove outdated DeepSeek R1 template tests (original template)
- test-chat.cpp: Improve test summary output with pass/fail breakdown
- test-grammar-parser.cpp: Add test for optional empty group (() | "a")
- server-context.cpp: Add allow_processing parameter to clear_slot for safer cleanup
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
