feat(wallet,content,seed): Fedimint dual-ecash, paid content streaming, seed ceremony

- Fedimint ecash alongside Cashu: fedimint-clientd (fmcd) HTTP bridge,
  fedimint_client, fedimint RPC, wallet wiring
- Paid peer content: content invoices + streaming content server + content RPCs
- Seed-phrase ceremony/reveal RPCs and CLI ceremony tool
- LND wallet, mesh status/messaging, app-stack (netbird HTTPS), and
  decoupled-update wiring; Fedimint Client core app in catalog

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker/fmcd/fmcd-run

@@ -0,0 +1,17 @@
+#!/bin/sh
+# Resilient launcher for fmcd.
+#
+# fmcd requires >=1 federation to boot — if the default federation is
+# unreachable at first boot it exits non-zero. Rather than let the container
+# crash-loop (and on a node, spam restarts), retry here with a backoff so the
+# join happens in the background once the federation becomes reachable. Once
+# fmcd is up it runs forever; this loop only re-runs it on exit.
+#
+# All config comes from FMCD_* env (FMCD_ADDR, FMCD_MODE, FMCD_DATA_DIR,
+# FMCD_INVITE_CODE, FMCD_PASSWORD), so fmcd needs no CLI args here.
+set -u
+while true; do
+    fmcd || true
+    echo "[fmcd-run] fmcd exited (federation unreachable?); retrying in 30s" >&2
+    sleep 30
+done