Stabilizes or optimizes Playwright E2E tests on one PR via a local-first loop, then ratifies with a single CI run. Pulls Dash0 spans (`git.pull_request_link`) as the historical baseline, then captures every iteration's evidence locally with `--trace=on` (same OTel exporter, same trace schema). Validation is empirical, not predictive: before commit, every new locator must resolve against source (static grep) or the live app (`locator.count()`); after commit, the fixed test must pass three consecutive local runs before the single push. Modes: `stabilize` (default) heals flaky / failing tests; `optimize` is report-only and ranks slow-action wins by measured ms saved. Refuses `.skip`, `.fixme`, `waitForTimeout`, or any check-weakening edit. Use when a PR has flaky or failing E2E tests or when you want to find slow tests worth tightening. Triggers on "stabilize this PR", "fix flaky e2e", "heal playwright on PR", "ui-e2e is failing", "self-heal e2e", "optimize e2e", "/e2e-pr-stabilizer".