Merge pull request #55 from garrytan/v0.3.6-qa-upgrades

feat: E2E observability + eval infrastructure + all skills templated

fix: auto-clear stale heartbeat when process is dead

Add PID to heartbeat file. eval-watch checks process.kill(pid, 0) and
auto-deletes the heartbeat when the PID is no longer alive — no manual
cleanup needed after crashed/killed E2E runs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

feat: eval-watch dashboard + observability unit tests (15 tests, 11 codepaths)

eval-watch: live terminal dashboard reads heartbeat + partial file every 1s,
shows completed/running tests, stale detection (>10min), --tail flag for
progress.log tail. Pure renderDashboard() function for testability.

observability.test.ts: unit tests for sanitizeTestName, heartbeat schema,
progress.log format, NDJSON file naming, savePartial() with _partial flag,
finalize() cleanup, diagnostic fields, watcher rendering, stale detection,
and non-fatal I/O guarantees.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>