Show the escalation ladder as a list, with who it would page and where it is

Team -> Escalation was the draft form on the page, which showed the
ladder only as inputs. It is now a table in the style of Switches and
Sources: a row per level with a status badge, who it pages, the wait
before the next level, and the open incidents currently waiting on it.
Below it, the repeat count, the fallback topic and when the ladder last
escalated (linking the incident). The editor moved into an "Edit ladder"
sheet, so a poll of the page underneath can no longer throw away half an
edit, and the page-level draft state went with it.

Targets are resolved to who they mean today, and the badge says what
would actually happen: Ready, Escalating (an unanswered incident has
climbed to level 2 or higher), or Pages nobody. The last is the one worth
seeing before an incident finds it: an empty rota, a person with no ntfy
topic or a disabled account each make a rung a silence with a number on
it, and the target says which. The rules are pageLevel's own, so the
page cannot promise a page the notifier would skip.

"Last escalated" comes from the escalated timeline events that already
exist, so there is no migration. Acknowledging or resolving takes an
incident off the ladder, so Escalating clears then while the history
stays.

API: GET /escalation gains status and waiting per level, username,
reachable and problem per target, and last_escalated_at and
last_escalated_incident_id. Output only and additive; PUT is unchanged
and terdut-tui needs nothing.

internal/web/static/app.css

@@ -365,7 +365,9 @@ input:focus, textarea:focus { outline: none; border-color: var(--accent); box-sh
    gone right, which is what the muted default already says. */
 .badge.st-dormant, .badge.st-never { background: var(--surface-2); color: var(--muted); }
 .badge.st-active { background: var(--ok-soft); color: var(--ok); }
-.badge.st-quiet { background: var(--warn-soft); color: var(--warn); }
+.badge.st-quiet, .badge.st-escalating { background: var(--warn-soft); color: var(--warn); }
+.badge.st-ready { background: var(--ok-soft); color: var(--ok); }
+.badge.st-unreachable { background: var(--crit-soft); color: var(--crit); }
 .badge.sev-critical { background: var(--crit-soft); color: var(--crit); }
 .badge.sev-warning { background: var(--warn-soft); color: var(--warn); }
 .badge.sev-info { background: var(--info-soft); color: var(--info); }
@@ -704,7 +706,7 @@ kbd {
 .card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
 .table-scroll { overflow-x: auto; margin-top: 12px; }
 .status-table th, .status-table td { white-space: nowrap; }
-.status-table td:nth-child(2) { white-space: normal; min-width: 12em; }
+.status-table td.wrap { white-space: normal; min-width: 12em; }
 .status-table .source-row td { border-bottom-style: dashed; }
 .status-table .source-row td:first-child { padding-left: 16px; }
 .source-labels { display: flex; flex-wrap: wrap; gap: 4px; align-items: center; }
@@ -827,6 +829,11 @@ button.rota-day:hover { background: var(--surface-2); }
 .ladder-head { display: flex; align-items: center; gap: 10px; margin-bottom: 6px; }
 .ladder-targets { display: flex; flex-direction: column; gap: 6px; margin-top: 8px; }
 .target-row { display: flex; gap: 6px; align-items: center; flex-wrap: wrap; }
+.ladder-editor { display: flex; flex-direction: column; gap: 10px; align-items: flex-start; margin-top: 12px; }
+/* A target that would not wake anybody says why, in place: it is the reason a
+   level is red, and the thing to go and fix. */
+.target-line { display: flex; gap: 8px; align-items: baseline; flex-wrap: wrap; }
+.target-problem { color: var(--crit); font-size: 12px; font-weight: 600; }
 
 /* An integration key is shown exactly once, so it should look like something
    to act on rather than another row of text. */