home-order follow-ups: fresh stamps for the blocked group, sort/display agreement, live Alt+N projection

Three follow-ups from the 1.19.0 review of the activity-ordered home screens:

- Hook events now ride the same debounced session state broadcast the
  working/idle handlers use. The blocked group ranks on lastActivityAt, and
  without this a permission prompt raised after page load kept ranking by
  whatever stamp the browser loaded with.

- A working row with no submit stamp now shows the lastActivityAt fallback
  its sort anchor already uses: a row must never be ranked by a number it
  does not display.

- Alt+digit resolves through the live-session projection the render paints
  (sessionOrder minus dead ids), so a stale id cannot shift every painted
  number off its target, web tabs included. New tests pin both surfaces to
  one shared order and the numbering to the live projection.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/web/public/app.js

@@ -1116,12 +1116,17 @@ class CodemanApp {
         if (digitMatch) {
           const idx = parseInt(digitMatch[1], 10) - 1;
           // Sessions occupy 1..N and web tabs continue from N+1, matching the
-          // numbers actually painted on the tabs.
-          if (idx < this.sessionOrder.length) {
+          // numbers actually painted on the tabs. Resolve through the same
+          // live-session projection the render paints: sessionOrder can
+          // transiently hold a dead id (delete raced against the order sync),
+          // and raw indexing then names the wrong tab for every key to its
+          // right, web tabs included.
+          const live = this.sessionOrder.filter((id) => this.sessions.has(id));
+          if (idx < live.length) {
             e.preventDefault();
-            this.selectSession(this.sessionOrder[idx]);
+            this.selectSession(live[idx]);
           } else {
-            const webIdx = idx - this.sessionOrder.length;
+            const webIdx = idx - live.length;
             const webId = (this.webviewOrder || [])[webIdx];
             if (webId) {
               e.preventDefault();