feat(scripts): android-build-async.sh — fire-and-forget APK builder

The existing build-tauri-android.sh holds an SSH connection open for
the entire Docker build (~10 min). Running it in the background kills
it when the SSH keepalive times out (~60s of silence during compile).

New script:
- uploads the build script to remote and launches it in a detached
  tmux session so it survives SSH disconnects
- exits immediately (fire-and-forget); build result arrives via ntfy
- --wait flag blocks + downloads APK when done (same as old script)
- same flags as the original: --init, --rust, --no-pull, --debug

Usage:
  ./scripts/android-build-async.sh          # fire and forget
  ./scripts/android-build-async.sh --wait   # block until APK downloaded
  ./scripts/android-build-async.sh --init --wait

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/android-build-async.sh

@@ -0,0 +1,122 @@
+#!/usr/bin/env bash
+# Fire-and-forget Android APK builder.
+#
+# Uploads the build script to SepehrHomeserverdk, starts it in a tmux
+# session so it survives SSH disconnects, then exits immediately.
+# Progress and the finished APK URL arrive via ntfy.sh/wzp.
+#
+# Usage:
+#   ./scripts/android-build-async.sh           # build current branch, arm64
+#   ./scripts/android-build-async.sh --init    # also run cargo tauri android init
+#   ./scripts/android-build-async.sh --rust    # force-clean Rust target cache
+#   ./scripts/android-build-async.sh --no-pull # skip git fetch on remote
+#   ./scripts/android-build-async.sh --wait    # block until done, then download APK
+#
+# When the build finishes, ntfy.sh/wzp will show:
+#   "WZP Tauri arm64 [<hash>] ready! <rustypaste-url>"
+# or on failure:
+#   "WZP Tauri Android build FAILED [<hash>] (line N) log: <url>"
+
+set -euo pipefail
+
+REMOTE_HOST="SepehrHomeserverdk"
+NTFY_TOPIC="https://ntfy.sh/wzp"
+LOCAL_OUTPUT="target/tauri-android-apk"
+TMUX_SESSION="wzp-android"
+REMOTE_LOG="/tmp/wzp-tauri-build.log"
+SSH_OPTS="-o ConnectTimeout=15 -o ServerAliveInterval=30 -o ServerAliveCountMax=6 -o LogLevel=ERROR"
+
+BRANCH="${WZP_BRANCH:-$(git -C "$(dirname "$0")/.." branch --show-current 2>/dev/null || echo "")}"
+DO_PULL=1
+DO_INIT=0
+BUILD_RELEASE=1
+REBUILD_RUST=0
+BUILD_ARCH="arm64"
+DO_WAIT=0
+
+for arg in "$@"; do
+    case "$arg" in
+        --pull)     DO_PULL=1 ;;
+        --no-pull)  DO_PULL=0 ;;
+        --init)     DO_INIT=1 ;;
+        --debug)    BUILD_RELEASE=0 ;;
+        --rust)     REBUILD_RUST=1 ;;
+        --wait)     DO_WAIT=1 ;;
+    esac
+done
+
+if [ -z "$BRANCH" ]; then
+    echo "ERROR: could not determine branch (detached HEAD?). Set WZP_BRANCH=name."
+    exit 1
+fi
+
+log()  { echo -e "\033[1;36m>>> $*\033[0m"; }
+err()  { echo -e "\033[1;31mERROR: $*\033[0m" >&2; }
+ssh_q() { ssh $SSH_OPTS "$REMOTE_HOST" "$@"; }
+
+# ── Step 1: upload the remote build script ──────────────────────────────────
+log "Uploading build script to $REMOTE_HOST..."
+# Re-use the existing full build script (it already handles all logic).
+scp $SSH_OPTS "$(dirname "$0")/build-tauri-android.sh" "$REMOTE_HOST:/tmp/wzp-tauri-build-full.sh"
+ssh_q "chmod +x /tmp/wzp-tauri-build-full.sh"
+
+# ── Step 2: launch in tmux (detached) ──────────────────────────────────────
+log "Starting build in tmux session '$TMUX_SESSION' on $REMOTE_HOST..."
+ssh_q "tmux kill-session -t $TMUX_SESSION 2>/dev/null; true"
+
+# The full script accepts flags directly; pass them through.
+REMOTE_FLAGS=""
+[ "$DO_PULL"       = "1" ] || REMOTE_FLAGS="$REMOTE_FLAGS --no-pull"
+[ "$DO_INIT"       = "1" ] && REMOTE_FLAGS="$REMOTE_FLAGS --init"
+[ "$BUILD_RELEASE" = "0" ] && REMOTE_FLAGS="$REMOTE_FLAGS --debug"
+[ "$REBUILD_RUST"  = "1" ] && REMOTE_FLAGS="$REMOTE_FLAGS --rust"
+
+# Run via WZP_BRANCH so the remote script picks up the right branch
+# (it calls `git branch --show-current` which would return the remote's
+# currently checked-out branch, not necessarily the one we want).
+ssh_q "tmux new-session -d -s $TMUX_SESSION \
+  'WZP_BRANCH=$BRANCH bash /tmp/wzp-tauri-build-full.sh $REMOTE_FLAGS \
+   2>&1 | tee $REMOTE_LOG; echo DONE_EXIT_CODE=\$? >> $REMOTE_LOG'"
+
+log "Build dispatched! Notification on ntfy.sh/wzp when done."
+echo ""
+echo "  Monitor : ssh $REMOTE_HOST 'tail -f $REMOTE_LOG'"
+echo "  Status  : ssh $REMOTE_HOST 'tail -5 $REMOTE_LOG'"
+echo "  Attach  : ssh $REMOTE_HOST 'tmux attach -t $TMUX_SESSION'"
+echo ""
+
+# ── Step 3 (optional --wait): block until done, download APK ───────────────
+if [ "$DO_WAIT" = "0" ]; then
+    exit 0
+fi
+
+log "Waiting for build to finish (monitoring $REMOTE_LOG)..."
+ssh_q "until grep -qE 'APK_REMOTE_PATH|FAILED|ERROR|DONE_EXIT_CODE' \
+    $REMOTE_LOG 2>/dev/null; do sleep 20; done"
+
+# Check for failure
+if ssh_q "grep -q 'FAILED\|ERROR' $REMOTE_LOG 2>/dev/null" && \
+   ! ssh_q "grep -q 'APK_REMOTE_PATH' $REMOTE_LOG 2>/dev/null"; then
+    err "Build failed — check ntfy or: ssh $REMOTE_HOST 'cat $REMOTE_LOG'"
+    exit 1
+fi
+
+# Grab APK paths from log
+APK_REMOTES=$(ssh_q "grep '^APK_REMOTE_PATH=' $REMOTE_LOG | cut -d= -f2-")
+if [ -z "$APK_REMOTES" ]; then
+    err "No APK_REMOTE_PATH in log — build may have failed silently"
+    ssh_q "tail -20 $REMOTE_LOG" >&2
+    exit 1
+fi
+
+mkdir -p "$LOCAL_OUTPUT"
+echo "$APK_REMOTES" | while IFS= read -r REMOTE_PATH; do
+    [ -z "$REMOTE_PATH" ] && continue
+    APK_NAME=$(basename "$REMOTE_PATH")
+    log "Downloading $APK_NAME..."
+    scp $SSH_OPTS "$REMOTE_HOST:$REMOTE_PATH" "$LOCAL_OUTPUT/$APK_NAME"
+    echo "  $LOCAL_OUTPUT/$APK_NAME ($(du -h "$LOCAL_OUTPUT/$APK_NAME" | cut -f1))"
+done
+
+log "Done! APKs in $LOCAL_OUTPUT/"
+ls -lh "$LOCAL_OUTPUT"/wzp-tauri-*.apk 2>/dev/null || true