Goblin P0-P3 backend: brand reskin, theme tokens, nostr payment subsystem

Infrastructure (P0): deployed nostr-rs-relay (wss://nrelay.us-ea.st) and the
goblin-nip05d NIP-05 service (goblin.st) on us-ea.st with TLS + DNS.

Brand & theme (P1): Goblin name/icon/data-dir (.goblin); three-theme token
system (light/dark/yellow) in gui/theme.rs with colors.rs remapped as a shim;
Geist + Geist Mono fonts; AppConfig theme/density/last_wallet_id.

Nostr subsystem (P2-P3): src/nostr/ with NIP-06 identity (seed-derived,
NIP-49 encrypted), per-wallet rkv archive, guarded ingest policy (never
auto-pays Invoice1; binds replies to the stored counterparty npub), NIP-17
send/receive pipeline, NIP-05 client. Relay traffic routed over the embedded
arti Tor client via a custom WebSocketTransport. Wired into Wallet lifecycle
and the task handler. 26 unit tests pass.

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

scripts/gen_icons.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Generate all Goblin app icons from img/goblin-icon.png (app icon)
+# and img/goblin-mask.png (black mascot art on transparency).
+# Requires ImageMagick (magick).
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+ICON=img/goblin-icon.png
+MASK=img/goblin-mask.png
+RES=android/app/src/main/res
+
+# Desktop window icon + in-app embeds.
+magick "$ICON" -resize 256x256 img/icon.png
+magick "$ICON" -resize 512x512 img/goblin-icon-512.png
+magick "$MASK" -channel RGB -fill white -colorize 100 img/goblin-mask-white.png
+magick img/goblin-mask-white.png -resize 128x128 img/goblin-mask-128.png
+magick img/goblin-mask-white.png -resize 64x64 img/goblin-mask-64.png
+
+# Android launcher icons.
+declare -A SIZES=( [mdpi]=48 [hdpi]=72 [xhdpi]=96 [xxhdpi]=144 [xxxhdpi]=192 )
+declare -A FG_SIZES=( [mdpi]=108 [hdpi]=162 [xhdpi]=216 [xxhdpi]=324 [xxxhdpi]=432 )
+for d in mdpi hdpi xhdpi xxhdpi xxxhdpi; do
+  s=${SIZES[$d]}; fg=${FG_SIZES[$d]}
+  # mascot occupies ~52% of the adaptive canvas (safe zone is 66%)
+  art=$(( fg * 52 / 100 ))
+  magick "$ICON" -resize ${s}x${s} "$RES/mipmap-$d/ic_launcher.png"
+  magick "$ICON" -resize ${s}x${s} "$RES/mipmap-$d/ic_launcher_round.png"
+  magick "$MASK" -resize ${art}x${art} -background none \
+    -gravity center -extent ${fg}x${fg} "$RES/mipmap-$d/ic_launcher_foreground.png"
+done
+
+echo "icons generated"