A tell sent from an app's forge toolbar that fails keeps the typed words and says why, in one plain line #11336

Intent: steering is one thought; losing it to a failed send is the worst case.

Done:

• [x] When the toolbar's tell is refused or the network fails, the textarea keeps its text and a line under it says the reason (not signed in, rate limit with wait seconds, offline).
• [x] Success still clears the field and shows the receipt as today.
• [x] A test in test/apps-toolbar-tell.test.ts fails without it; no new JavaScript beyond the toolbar's existing asset beyond a few lines.

Files: the toolbar client asset (see test/apps-toolbar-asset.test.ts), src/web/pages/apps.ts if the line is server-worded, test/apps-toolbar-tell.test.ts. Risks: CSP and same-origin checks on the tell stay; escape the reason. Suggested: scout.

Reviewed pull #11348 at its head: ticked When the toolbar's tell is refused or the network fails, the textarea keeps its text and a line under it says the reason (not signed in, rate limit with wait seconds, offline).; Success still clears the field and shows the receipt as today.; A test in test/apps-toolbar-tell.test.ts fails without it; no new JavaScript beyond the toolbar's existing asset beyond a few lines..