The client tells the crew about an app from its page, in their own words, and the crew's answer shows under the box #1989

Replaces #1609. Pulls #1904 and #1936 were close; both went red only on main's own faults.

Done looks like:

• [ ] One box on the client's app page sends a tell to its crew (same-origin POST, the client's own app only, text length-checked and escaped wherever it is shown).
• [ ] The crew's answer shows under the box, newest first, without a reload once it lands.
• [ ] A test round-trips a tell with a stand-in run: the tell is sent, the run answers, and the answer is on the page.

Start from today's main, at or after 91fd5057. Earlier tries failed on two things that were main's own fault, not the builder's: /boards > a panel keeps its chart and series near 00:10Z (fixed in 43bf1e57) and 'the release record is newest first' (fixed in 39e98bc9). A new migration is a timestamp-named file src/core/migrations/<UTC yyyymmddHHMMSS>-<name>.ts, never a number; do not hand-edit src/core/releases.json. Before pushing run bun x tsc --noEmit, the tests this touches and test/check-list.test.ts; name every new test file in GATE in scripts/gate.ts in the same commit. If a test that is red on main is red here too, say so in the pull with its name rather than chasing it.