feat(daily-run): 预检存档截图便于诊断坏首启画面

坏首启的画面至今只能靠体积推测；预检现在每 30 秒把采样帧存到
artifacts/preflight/（每轮运行开始时清空），坏首启次日可直接查看
游戏到底停在什么画面上，再设计针对性点按。

bin/maa-online-daily-run

@@ -35,6 +35,12 @@ ATTEMPT_MAX_SECONDS="${MAA_ONLINE_ATTEMPT_MAX_SECONDS:-3000}"  # per-attempt cei
 # while the game does first-login resource processing; without this, MAA burns
 # the whole attempt (and its quota) failing recognition on every task.
 PREFLIGHT_MAX_SECONDS="${MAA_ONLINE_PREFLIGHT_MAX_SECONDS:-780}"
+# Archive pre-flight screenshots (one every 30s) so a bad first boot can be
+# diagnosed visually afterwards: the bad screen is static, so a handful of
+# saved frames tell us exactly what the game was showing.
+PREFLIGHT_SHOT_DIR="${MAA_ONLINE_PREFLIGHT_SHOT_DIR:-$LOG_DIR/preflight}"
+rm -rf "$PREFLIGHT_SHOT_DIR"
+mkdir -p "$PREFLIGHT_SHOT_DIR"
 
 mkdir -p "$LOG_DIR"
 
@@ -107,13 +113,16 @@ fi
 # Screen classes by PNG size, calibrated on real captures (2026-09-23):
 #   black/loading <20KB | login 200-350KB (开始唤醒) | title ~480KB |
 #   announcement/menu >=650KB (hand off to MAA)
-preflight() { # arg1: max seconds; returns 0 once the screen looks in-game
-    local max="$1" elapsed=0 last_action=-20 ready_hits=0
+preflight() { # arg1: max seconds, arg2: attempt no.; returns 0 once the screen looks in-game
+    local max="$1" attempt_no="${2:-x}" elapsed=0 last_action=-20 ready_hits=0
     local png=/tmp/maa-preflight.png
     while [ "$elapsed" -lt "$max" ]; do
         if api GET /screencap > "$png" 2>/dev/null; then
             local size
             size=$(stat -c %s "$png" 2>/dev/null || echo 0)
+            if [ $((elapsed % 30)) -eq 0 ]; then
+                cp "$png" "$PREFLIGHT_SHOT_DIR/a${attempt_no}-t$(printf '%04d' "$elapsed").png" 2>/dev/null
+            fi
             if [ "$size" -ge 650000 ]; then
                 # Require the in-game-class screen to be stable: a single large
                 # frame can still be a loading/transition screen (2026-09-25
@@ -181,7 +190,7 @@ while [ "$attempt" -lt "$MAX_ATTEMPTS" ]; do
         continue
     fi
     echo "[daily-run] attempt $attempt: preflight: waiting for a recognizable game screen (max ${PREFLIGHT_MAX_SECONDS}s) ..."
-    if ! preflight "$PREFLIGHT_MAX_SECONDS"; then
+    if ! preflight "$PREFLIGHT_MAX_SECONDS" "$attempt"; then
         REASON="preflight timed out after ${PREFLIGHT_MAX_SECONDS}s; game screen never became ready"
         echo "[daily-run] attempt $attempt failed: $REASON; releasing cloud session" >&2
         api POST /exit >/dev/null 2>&1 || true