feat(web): deploy wizard polls async lifecycle instead of holding HTTP

- New useLifecyclePolling(ids, intervalMs) hook: polls
  GET /deckies/lifecycle?ids=... every 2s until every row is terminal,
  surfaces transient HTTP failures without giving up.
- DeployWizard: drops the 180s axios timeout and the fake-log-driven
  deployOk flag. After POST 202, sets lifecycle_ids -> the hook drives
  the per-decky pill grid (PENDING / RUNNING / SUCCEEDED / FAILED).
  Real terminal lines stream into the log as rows resolve. Auto-close
  on all-success after 700ms.
- DeckyFleet.css: .lifecycle-grid + .lifecycle-pill in the existing
  fleet vocabulary; running pill pulses, failed pill borders alert.
- Existing 4 wizard render tests still pass; 4 new hook tests cover
  empty ids / single-success / polling-until-terminal / HTTP error.

decnet_web/src/hooks/useLifecyclePolling.ts

@@ -0,0 +1,84 @@
+import { useEffect, useRef, useState } from 'react';
+import api from '../utils/api';
+
+export type LifecycleStatus = 'pending' | 'running' | 'succeeded' | 'failed';
+
+export interface LifecycleRow {
+  id: string;
+  decky_name: string;
+  host_uuid: string | null;
+  operation: 'deploy' | 'mutate';
+  status: LifecycleStatus;
+  error: string | null;
+  started_at: string;
+  updated_at: string;
+  completed_at: string | null;
+}
+
+const TERMINAL = new Set<LifecycleStatus>(['succeeded', 'failed']);
+
+/**
+ * Poll ``GET /deckies/lifecycle?ids=…`` every ``intervalMs`` until every
+ * row reaches a terminal status.  Returns the latest rows, a derived
+ * ``done`` flag, and any HTTP failure that surfaced on the last tick.
+ *
+ * Polling stops automatically once all rows are terminal (or when
+ * ``ids`` becomes empty / unmounts).  Pass an empty array to disable.
+ */
+export function useLifecyclePolling(
+  ids: string[],
+  intervalMs: number = 2000,
+): { rows: LifecycleRow[]; done: boolean; error: string | null } {
+  const [rows, setRows] = useState<LifecycleRow[]>([]);
+  const [error, setError] = useState<string | null>(null);
+  const cancelled = useRef(false);
+
+  useEffect(() => {
+    cancelled.current = false;
+    if (ids.length === 0) {
+      setRows([]);
+      return () => { cancelled.current = true; };
+    }
+
+    let timer: number | undefined;
+
+    const tick = async () => {
+      try {
+        const { data } = await api.get<{ rows: LifecycleRow[] }>(
+          '/deckies/lifecycle',
+          // axios encodes array params as repeated ?ids=… when
+          // paramsSerializer isn't overridden — matches FastAPI's expected
+          // shape for List[str] Query params.
+          { params: { ids }, paramsSerializer: { indexes: null } },
+        );
+        if (cancelled.current) return;
+        const next = data?.rows ?? [];
+        setRows(next);
+        setError(null);
+        const allDone = next.length === ids.length
+          && next.every((r) => TERMINAL.has(r.status));
+        if (!allDone) {
+          timer = window.setTimeout(tick, intervalMs);
+        }
+      } catch (e: unknown) {
+        if (cancelled.current) return;
+        const err = e as { message?: string };
+        setError(err?.message || 'Lifecycle poll failed');
+        timer = window.setTimeout(tick, intervalMs);
+      }
+    };
+
+    tick();
+    return () => {
+      cancelled.current = true;
+      if (timer !== undefined) window.clearTimeout(timer);
+    };
+  // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [ids.join('|'), intervalMs]);
+
+  const done = ids.length > 0
+    && rows.length === ids.length
+    && rows.every((r) => TERMINAL.has(r.status));
+
+  return { rows, done, error };
+}