docs: add cargo install installation method to README

fix: convert let chains to nested if statements for Rust 2021 compatibility

chore: update package metadata for crates.io

Merge branch 'main' of github.com:hotea/aiclient-api

feat: Add usage tracking and unified format configuration

Initial commit

fix: resolve clippy warnings across codebase

test: add end-to-end integration tests with mock provider

fix: rate limiter ConnectInfo, TOCTOU race, format-aware middleware errors

feat: add SIGHUP config hot-reload

feat: format-aware error responses

feat: add auth and rate-limit middleware

fix: code quality improvements (size cap, CSRF, url decode, TOCTOU, async IO)

fix: spec compliance fixes (control methods, crypto PKCE randomness)

feat: implement Kiro provider (CodeWhisperer client)