Flake dashboard: 4-column table, clickable streak squares

Misha reviewed a live mock on issue #2580 (2026-09-04) and approved the layout.

Status#

Implemented: 4-column render, commit-linked squares, contract 0.4.0 (journal refold backfills links for existing history). 21/21 harness tests, typecheck/lint/knip clean. Awaiting CI + review.

Motivation#

The 9-column table is ugly and mostly whitespace. Collapse to test | info | stats | streak with <br>-separated lines inside the info and stats cells. Bonus (requested): each 🟩/🟥/❌ square links to the commit that produced that outcome, so eyeballing a red square is one click from the run.

Checklist#

• Render: 4 columns per the approved mock — info = pattern: /…/ + suites: … + proposed: … (proposed line only when non-empty); stats = runs: + flake rate: + last flake: with human-readable UTC dates ("Sep 4, 7:16am"); streak = the emoji bar with the numeric default-branch streak as a second line (8× pass (main)) when present.
• Clickable squares: recent entries become { outcome, commit } folded from the run-recorded payload's commit; render each square as [🟩](https://github.com/<owner>/<repo>/commit/<sha>) (owner/repo from the birth certificate). The commit page links on to its check runs. GitHub run/check URLs and Depot run URLs are NOT stored — the commit is already in every event and is stable vocabulary; deeper links can come later if commit pages prove one click too far.
• Contract bump 0.3.0 → 0.4.0: recent's shape change refolds the journal, which backfills commit links for all existing history.
• Update flake-dashboard.test.ts render assertions.

Notes#

• The live mock (issue edit 2026-09-04T08:39:56Z) is the source of truth for layout; it gets overwritten by the next real render.
• Emoji legend moves into the intro sentence ("Streak = last 10 recorded outcomes on any branch, oldest→newest").