Bulk extend client expiry / traffic + clients page polish (#4499)

* chore(sub): drop unused getFallbackMaster

projectThroughFallbackMaster fully supersedes it for both
panel-tracked and legacy unix-socket fallbacks.

* feat(clients): bulk extend expiry / traffic for selected clients

Adds POST /panel/api/clients/bulkAdjust which shifts ExpiryTime by
addDays and TotalGB by addBytes for every email in one request. The
endpoint is wired into the clients page through a new ClientBulkAdjustModal
that opens from the existing multi-select toolbar.

Clients with unlimited expiry (expiryTime=0) or unlimited traffic
(totalGB=0) are skipped for the corresponding field so bulk extend
never accidentally converts an unlimited client to a limited one.
Negative values are allowed for refunds / corrections.

Translations added for all 13 locales.

* fix(db): silence GORM record-not-found spam in debug mode

getSetting handles ErrRecordNotFound via database.IsNotFound and falls
back to defaults, but GORM's Default logger still logs each miss as an
error. With periodic jobs reading unset keys (xrayTemplateConfig,
externalTrafficInformEnable) the panel log flooded thousands of times.
Switch to a logger.New with IgnoreRecordNotFoundError=true so legitimate
slow-query and SQL traces still surface in debug mode.

* fix(clients): include inboundsById in columns memo deps

Without it, the table's first paint captured an empty inboundsById and
rendered each attached inbound as #<id>. Once a sort/filter forced the
memo to rebuild it self-corrected, hence the visible flicker on reload.

* fix(clients): handle delayed-start expiry in bulk adjust

Negative ExpiryTime encodes a delay duration (magnitude = ms until
the trial begins on first use). Adding positive addDays was simply
arithmetically added, so e.g. a -7d delay + 30d turned into +23d
since epoch (1970), making the client instantly expired.

Branch on sign now: positive ExpiryTime extends additively, negative
extends by subtracting so the value stays negative (more delay).
Cross-sign reductions are skipped with an explicit reason instead of
silently corrupting the field.

* fix(clients): step traffic input by 1 GB instead of 0.1

The +/- buttons on the Total Sent/Received field nudged in 0.1 GB
increments which is too granular for typical use. Set step=1 so each
press moves a whole GB; users can still type decimal values directly.

* fix(inbounds): step Total Flow input by 1 GB instead of 0.1

Matches the same nudge fix applied to the client form's Total
Sent/Received field.

web/translation/ja-JP.json

@@ -479,8 +479,14 @@
       "deleteConfirmTitle": "クライアント {email} を削除しますか?",
       "deleteConfirmContent": "クライアントを関連付けされたすべてのインバウンドから削除し、トラフィック記録も破棄します。元に戻せません。",
       "deleteSelected": "削除 ({count})",
+      "adjustSelected": "調整 ({count})",
       "bulkDeleteConfirmTitle": "{count} 件のクライアントを削除しますか?",
       "bulkDeleteConfirmContent": "選択された各クライアントを関連付けされたすべてのインバウンドから削除し、トラフィック記録も破棄します。元に戻せません。",
+      "bulkAdjustTitle": "{count} 件のクライアントを調整",
+      "bulkAdjustHint": "正の値は延長、負の値は短縮します。無期限の有効期限または無制限のトラフィックを持つクライアントは、その項目についてスキップされます。",
+      "bulkAdjustNothing": "適用する前に日数またはトラフィックを設定してください。",
+      "addDays": "日数を追加",
+      "addTrafficGB": "トラフィックを追加 (GB)",
       "delDepleted": "使い切ったクライアントを削除",
       "delDepletedConfirmTitle": "使い切ったクライアントを削除しますか?",
       "delDepletedConfirmContent": "トラフィック上限に達したか有効期限が切れたクライアントをすべて削除します。元に戻せません。",
@@ -503,6 +509,8 @@
         "bulkDeletedMixed": "{ok} 件削除、{failed} 件失敗",
         "bulkCreated": "{count} 件のクライアントを作成しました",
         "bulkCreatedMixed": "{ok} 件作成、{failed} 件失敗",
+        "bulkAdjusted": "{count} 件のクライアントを調整しました",
+        "bulkAdjustedMixed": "{ok} 件調整、{skipped} 件スキップ",
         "delDepleted": "使い切った {count} 件のクライアントを削除しました"
       }
     },