fix(cl): just retrieve top-k 3 for context to prevent token exceed

...ama/templates/components/engines/python/agent/__init__.py

...lama/templates/components/engines/python/chat/__init__.py

.../templates/components/vectordbs/typescript/mongo/index.ts

...a/templates/components/vectordbs/typescript/none/index.ts

...ama/templates/components/vectordbs/typescript/pg/index.ts