feat(organize): separate source dir from destination dir (从源目录整理到目的地目录)

Previously organize only exposed a single 'target dir' that was actually
the destination, conflating 源目录 (where files to organize live) with
目的地目录 (where organized files go). Add an explicit source directory:

- OrganizeOptions gains SourcePath; DestPath replaces the old TargetPath
  (destination) for clarity. New organize.source_dir setting + source_path
  request override; resolveSourceRoot falls back to library path.
- OrganizeLibraryWithOptions only organizes media located under the source
  root, so operators can point at a specific download/staging folder and
  organize into a distinct destination.
- Handler accepts source_path/dest_path (target_path kept as a deprecated
  alias for the destination, backward compatible).
- Settings page splits into 整理源目录(待整理) + 整理目的地目录; Tools organize
  panel exposes 源目录 + 目的地目录 inputs with clear copy.

Defaults are unchanged (source = destination = library path) so existing
setups behave identically. Adds a regression test that organize is scoped
to the source directory.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

web/src/api/tools.ts

@@ -5,8 +5,10 @@ import { api } from './client'
 // dispatching a test notification through the configured channels.
 // OrganizeOverrides are optional single-request overrides for an organize
 // action. Empty fields fall back to the system settings.
+// source_path = 源目录（待整理文件所在），dest_path = 目的地目录（整理输出到哪里）。
 export interface OrganizeOverrides {
-  target_path?: string
+  source_path?: string
+  dest_path?: string
   transfer_mode?: string
 }
 

web/src/pages/SettingsPage.tsx

@@ -152,10 +152,17 @@ const GROUPS: SettingGroup[] = [
         hint: '根据元数据（语言/国家/类型）自动分类到子目录（如：华语电影、欧美剧、日番）',
       },
       {
-        key: 'organize.target_dir',
-        label: '整理目标目录',
+        key: 'organize.source_dir',
+        label: '整理源目录（待整理）',
         type: 'text',
-        hint: '留空则默认整理到各媒体库对应路径（见下方参考）',
+        hint: '从该目录读取待整理文件；留空则默认整理整个媒体库（媒体库路径）。',
+        placeholder: '/mnt/downloads',
+      },
+      {
+        key: 'organize.target_dir',
+        label: '整理目的地目录',
+        type: 'text',
+        hint: '整理后输出到该目录；留空则默认整理到各媒体库对应路径（见下方参考）。与「源目录」相互独立。',
         placeholder: '/mnt/media/organized',
       },
       {
@@ -388,7 +395,7 @@ export function SettingsPage() {
         <div className="glass-panel">
           <div className="mb-3 flex items-center gap-2 text-sm text-ink-100">
             <FolderOpen size={16} className="text-brand-500" />
-            <span>默认整理路径参考（未设目标目录时按媒体库归类）</span>
+            <span>默认整理路径参考（未设目的地目录时按媒体库归类）</span>
           </div>
           <table className="w-full text-left text-sm">
             <thead className="text-xs uppercase tracking-wider text-sand-500">

web/src/pages/ToolsPage.tsx

@@ -61,13 +61,15 @@ function OrganizePanel() {
   const [smartClassify, setSmartClassify] = useState(false)
   const [loadingSettings, setLoadingSettings] = useState(true)
 
-  // 单次整理覆盖项：留空则沿用设置页的默认整理目录与转移方式。
-  const [targetPath, setTargetPath] = useState('')
+  // 单次整理覆盖项：留空则沿用设置页的默认源目录/目的地目录与转移方式。
+  const [sourcePath, setSourcePath] = useState('')
+  const [destPath, setDestPath] = useState('')
   const [transferMode, setTransferMode] = useState('')
 
   const overrides = () => {
-    const o: { target_path?: string; transfer_mode?: string } = {}
-    if (targetPath.trim()) o.target_path = targetPath.trim()
+    const o: { source_path?: string; dest_path?: string; transfer_mode?: string } = {}
+    if (sourcePath.trim()) o.source_path = sourcePath.trim()
+    if (destPath.trim()) o.dest_path = destPath.trim()
     if (transferMode) o.transfer_mode = transferMode
     return o
   }
@@ -162,14 +164,27 @@ function OrganizePanel() {
         </div>
       )}
 
-      <div className="grid gap-3 rounded-xl border border-gray-200 bg-gray-50 p-3 sm:grid-cols-2">
+      <p className="text-xs text-sand-500">
+        整理是「<b>从源目录整理到目的地目录</b>」：源目录是待整理文件当前所在的位置，目的地目录是整理后输出的位置。两者留空则分别沿用设置页的默认值（默认源目录 = 媒体库路径）。
+      </p>
+
+      <div className="grid gap-3 rounded-xl border border-gray-200 bg-gray-50 p-3 sm:grid-cols-3">
         <label className="space-y-1">
-          <span className="text-xs text-ink-50">整理目标目录（可选，覆盖默认设置）</span>
+          <span className="text-xs text-ink-50">源目录（待整理，可选）</span>
           <input
             className="input-base w-full"
-            placeholder="留空则使用「整理目标目录」设置或媒体库路径"
-            value={targetPath}
-            onChange={(e) => setTargetPath(e.target.value)}
+            placeholder="留空则使用「整理源目录」设置或媒体库路径"
+            value={sourcePath}
+            onChange={(e) => setSourcePath(e.target.value)}
+          />
+        </label>
+        <label className="space-y-1">
+          <span className="text-xs text-ink-50">目的地目录（整理输出，可选）</span>
+          <input
+            className="input-base w-full"
+            placeholder="留空则使用「整理目的地目录」设置或媒体库路径"
+            value={destPath}
+            onChange={(e) => setDestPath(e.target.value)}
           />
         </label>
         <label className="space-y-1">