fix client.go duplicate code

fix duplicate code in client.go

fix cookie injection position

add session cookies to upstream requests

add missing url params

add missing body fields for z.ai

add x-region header

feat: lowercase model ids, add glm-5, socks5 proxy pool, remove arm build

fix: inject system and tool prompts as user+assistant pairs

fix: improve tool calling reliability with multi-format parsing and Delta pointer fix

feat: support tool/function calling (OpenAI compatible)

refactor: split internal package into domain-based sub-packages