Signals: feeds made from your subscriptions, picked by Jev (#254)

A Signal is a name and keywords. A task beside DeadAir's asks TypeSafe's Jev, on the owner's own
key, about each item of their subscribed feeds from the last 30 days and every new one: one call
an item, one noul question for each of their Signals still to hear about it, 0.5 or more a fit.
Every verdict is kept, fitting or not, in signal_verdicts, so nothing is asked twice, and new
keywords drop a Signal's verdicts to be judged afresh. A key TypeSafe refuses (401/402/403) is
passed over until its owner saves another, so a bad key is not sent the whole queue.

A Signal's items come through entries_where with an EXISTS on its hits, so filters, search, sort
and read state are an ordinary list's, and reading an item in a Signal reads it in its feed.

The page shows Signals under the places, with New signal, and Settings takes the TypeSafe key,
which is never sent back. The browser suite stubs Jev in the fixture server (IPX_TYPESAFE_URL).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/util.ts

@@ -13,6 +13,8 @@ const esc = (s: string|null|undefined) => (s??'').replace(/[&<>"']/g,c=>ESCAPED[
 // the button's own colour. To add one, copy the path from svgs/<style>/<name>.svg at the same tag.
 const fa=(box: string,body: string)=>`<svg class="i" viewBox="${box}" aria-hidden="true">${body}</svg>`;
 const ICON: Record<string,string>={
+// Waves either side of a point: a Signal (#254).
+signal:fa('0 0 512 512','<g fill="none" stroke="currentColor" stroke-width="44" stroke-linecap="round"><path d="M136 136a170 170 0 0 0 0 240"/><path d="M376 136a170 170 0 0 1 0 240"/><path d="M204 196a85 85 0 0 0 0 120"/><path d="M308 196a85 85 0 0 1 0 120"/></g><circle cx="256" cy="256" r="38" fill="currentColor"/>'),
   share:fa('0 0 512 512','<path fill="currentColor" d="M384 192c53 0 96-43 96-96s-43-96-96-96-96 43-96 96c0 5.4 .5 10.8 1.3 16L159.6 184.1c-16.9-15-39.2-24.1-63.6-24.1-53 0-96 43-96 96s43 96 96 96c24.4 0 46.6-9.1 63.6-24.1L289.3 400c-.9 5.2-1.3 10.5-1.3 16 0 53 43 96 96 96s96-43 96-96-43-96-96-96c-24.4 0-46.6 9.1-63.6 24.1L190.7 272c.9-5.2 1.3-10.5 1.3-16s-.5-10.8-1.3-16l129.7-72.1c16.9 15 39.2 24.1 63.6 24.1z"/>'), // solid/share-nodes
   plus:fa('0 0 448 512','<path fill="currentColor" d="M256 64c0-17.7-14.3-32-32-32s-32 14.3-32 32l0 160-160 0c-17.7 0-32 14.3-32 32s14.3 32 32 32l160 0 0 160c0 17.7 14.3 32 32 32s32-14.3 32-32l0-160 160 0c17.7 0 32-14.3 32-32s-14.3-32-32-32l-160 0 0-160z"/>'), // solid/plus
   circleMinus:fa('0 0 512 512','<path fill="currentColor" d="M512 256A256 256 0 1 0 0 256a256 256 0 1 0 512 0zM184 232l144 0c13.3 0 24 10.7 24 24s-10.7 24-24 24l-144 0c-13.3 0-24-10.7-24-24s10.7-24 24-24z"/>'), // solid/circle-minus, for Unsubscribe
@@ -218,7 +220,7 @@ function nav(on: boolean){ $('#sidebar').classList.toggle('open',on); $('#scrim'
 
 /* ---------------- state ---------------- */
 const S: State = {
-  feeds:[],
+  feeds:[], signals:[],
   // Which feed (or place) and which tab were open last time, so a refresh lands back where
   // you were instead of jumping to the first feed alphabetically.
   feed:(()=>{ try{ return localStorage.getItem('ipx.feed'); }catch{ return null; } })(),