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

feat: E2E observability + eval infrastructure + all skills templated

fix: never clean up observability artifacts — partial file persists after finalize

Removing the _partial-e2e.json deletion from finalize(). These are small files
on a local disk and their persistence is the whole point of observability.

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>