GLM/ZhipuAI rejects system role messages with 422 'Input should be
user or assistant'. When memory injection adds a system-role message,
GLM combo targets fail because the system message survives into the
upstream request.
Fix:
- injection.ts: add glm, glmt, glm-cn, zai, qianfan to
PROVIDERS_WITHOUT_SYSTEM_MESSAGE so memory is injected as user role
- roleNormalizer.ts: add exact 'glm' model match to
MODELS_WITHOUT_SYSTEM_ROLE for Pollinations and bare model ids
Test: 22 new unit tests covering all GLM variants + regression checks
for openai/anthropic providers.
Closes#1701
