One test proves every kind of feed post reaches its files, diff, run or terminal in two taps #7754

For: P1 Feed. Its test says: from any post a person reaches its files, diff, run or terminal in two taps. The feed builds posts of kinds milestone, decision, map, ask, cost, run, pull, look and release in src/feed/items.ts, but no test proves the depth behind each one is two links away.

Done looks like:

• [ ] A new test/feed-two-taps.test.ts boots one forge, makes one repository with an event of each feed kind it can produce (a pull opened and merged, a run, a look, a release, an ask, a decision), and reads / signed in as the owner.
• [ ] For each post, the test follows the post's own link (tap 1) and finds on that page a link to the depth that kind promises (tap 2): pull to its diff (/…/pulls/N/files or its change page), run to its log, look to its picture, release to its commit tree, ask to the thing asked about. It asserts that each link answers 200.
• [ ] A kind whose depth is three taps or more today is fixed in its post's link (in src/feed/items.ts) or on the page it lands on, and named in the pull. Change no test that already passes.

Files: test/feed-two-taps.test.ts, and only if a kind fails: src/feed/items.ts or that kind's page. Risks: the test must not depend on wall-clock ranking; read the item list through GET /api/v1/feed if the page orders unpredictably.