refactor: remove redundant per-reviewer summary step before final conclusion

feat: add verified conclusion step that cross-checks summary against actual code

feat: support specifying models for CLI providers via colon syntax

fix: handle large PR diffs that exceed GitHub's 20k line limit

feat: add general discussion phase before issue-by-issue review

fix: strengthen language enforcement by injecting instructions into system prompt prefix

fix: improve inline PR comment placement with content-based matching and full diff fallback

fix: auto-select all reviewers in non-TTY mode to prevent hanging

chore: move typescript to devDependencies, remove unused readline package

fix: add SIGKILL fallback after SIGTERM timeout in CLI providers

fix: add retry with backoff to all CLI providers and Gemini streaming

feat: pre-flight check for CLI binaries with friendly error messages

fix: register exit handler to clean up temp prompt files

fix: single reviewer failure no longer terminates entire review session

fix: prevent command injection in history-collector via spawnSync