feat: configurable builder CLI (claude/codex) with smart file reading

chore: bump Codex model from gpt-5.2-codex to gpt-5.4-codex

docs(sentinel): add implementation plan and test package init

feat(sentinel): add ncdev fix and ncdev serve CLI commands

feat(sentinel): add frontend test type detection and monorepo subdir detection

feat(sentinel): add HTTP intake API with /reports, /runs, /health endpoints

feat(sentinel): add run_v2_fix() engine function with report loading

feat(sentinel): add materialize_fix_from_report() to jobs.py

feat(sentinel): add reproduction and fix prompt templates

feat(sentinel): add sentinel config section with service registry, rate limits, callback

feat(sentinel): add callback HTTP client with retry logic

feat(sentinel): add circuit breaker, scope guard, deduplication, cooldown

feat(sentinel): add Sentinel models, enums, and types to v2/models.py

test(sentinel): add sample failure report fixtures from contract

feat: add frontend design stack to CLAUDE.md for generated projects