feat: install announcer skill to user scope (~/.claude/skills/)

feat: support GitHub URLs for target project resolution

refactor: replace script-based announcer with Claude Code skill

feat: add announcer as Claude Code skill for interactive sessions

feat: add announcer — real-time pipeline narration via rail.log

docs: rewrite README with problem/insight/solution narrative

test: expand test suite from 54 to 116 tests

docs: add The Journey visualization to README

rename: adopt rail metaphor for internal plumbing

docs: highlight contract-based separate evaluator in README

docs: add Harness Design for Long-Running Apps reference

rename: BashRalph → RailRalph — Ralph on deterministic rails

feat: separate evaluator — contract-driven E2E verification

fix: resolve claude -p prompt overflow and review timing issues

test: add tests for AC parsing, verdict detection, ALLOWED_TOOLS, and awk extraction