Feature: Add configurable screen-preview quality levels menu

Add a "屏幕预览质量等级 (Screen Preview Quality Levels)" item to the
"高级 (Advanced)" menu that opens a dialog to edit the six preset
PreviewProfile levels (target encode width and JPEG quality) used by the
double-click single-preview and loop-snapshot floating windows. The dialog
edits a working copy in a full grid with per-field validation and a
restore-defaults button; on OK it persists the values to the [preview] INI
section.

ChooseScreenPreviewParams now reads from GetPreviewProfileCfg instead of the
hardcoded GetScreenPreviewProfile table, so preview requests sent after a
change use the configured parameters. LoadPreviewProfilesFromCfg loads the
saved levels at startup, falling back to the built-in defaults. Added
en_US/de_DE/zh_TW translations for the new menu and dialog strings.

Co-Authored-By: deepseek-v4-pro

server/2015Remote/CPreviewLevelsDlg.h

@@ -0,0 +1,121 @@
+// CPreviewLevelsDlg.h
+// 屏幕预览质量等级配置对话框：编辑 6 档 PreviewProfile（编码宽度 / JPEG 质量）。
+// 纯主控端 UI 偏好，持久化由 CMy2015RemoteDlg::SavePreviewProfilesToCfg() 负责。
+// 仅在 2015RemoteDlg.cpp 中 include 一次（头文件内联实现，勿多处包含）。
+#pragma once
+
+#include "LangManager.h"
+
+class CPreviewLevelsDlg : public CDialog
+{
+public:
+    enum { IDD = IDD_PREVIEW_LEVELS };
+
+    // profiles: 指向 6 元素 PreviewProfile 数组，确认后写回
+    CPreviewLevelsDlg(PreviewProfile* profiles, CWnd* pParent = NULL)
+        : CDialog(CPreviewLevelsDlg::IDD, pParent), m_profiles(profiles)
+    {
+    }
+
+protected:
+    PreviewProfile* m_profiles;
+    PreviewProfile  m_working[QUALITY_COUNT];
+
+    static const char* LevelName(int i)
+    {
+        static const char* names[QUALITY_COUNT] = {
+            "Ultra", "High", "Good", "Medium", "Low", "Minimal"
+        };
+        return (i >= 0 && i < QUALITY_COUNT) ? names[i] : "?";
+    }
+
+    void LoadToControls()
+    {
+        CString s;
+        for (int i = 0; i < QUALITY_COUNT; i++) {
+            s.Format(_T("%d"), m_working[i].maxWidth);
+            SetDlgItemText(IDC_PLEVEL_WIDTH + i, s);
+            s.Format(_T("%d"), m_working[i].jpegQuality);
+            SetDlgItemText(IDC_PLEVEL_QUALITY + i, s);
+        }
+    }
+
+    bool ReadInt(int id, int& out)
+    {
+        CString s;
+        GetDlgItemText(id, s);
+        s.Trim();
+        if (s.IsEmpty()) return false;
+
+        int v = 0;
+        for (int k = 0; k < s.GetLength(); k++) {
+            TCHAR ch = s[k];
+            if (ch < _T('0') || ch > _T('9')) return false;
+            v = v * 10 + (ch - _T('0'));
+        }
+        out = v;
+        return true;
+    }
+
+    bool ReadFromControls(CString& err)
+    {
+        for (int i = 0; i < QUALITY_COUNT; i++) {
+            int w, q;
+            if (!ReadInt(IDC_PLEVEL_WIDTH + i, w))
+            { err.Format(_T("等级 %s 的最大宽度不是有效数字"), LevelName(i)); return false; }
+            if (!ReadInt(IDC_PLEVEL_QUALITY + i, q))
+            { err.Format(_T("等级 %s 的 JPEG 质量不是有效数字"), LevelName(i)); return false; }
+
+            if (w < 64 || w > 2560)
+            { err.Format(_T("等级 %s 的最大宽度需在 64~2560 之间"), LevelName(i)); return false; }
+            if (q < 1 || q > 100)
+            { err.Format(_T("等级 %s 的 JPEG 质量需在 1~100 之间"), LevelName(i)); return false; }
+
+            m_working[i].maxWidth    = w;
+            m_working[i].jpegQuality = q;
+        }
+        return true;
+    }
+
+    void ResetToDefaults()
+    {
+        for (int i = 0; i < QUALITY_COUNT; i++) {
+            m_working[i] = GetScreenPreviewProfile(i);
+        }
+        LoadToControls();
+    }
+
+    virtual BOOL OnInitDialog() override
+    {
+        CDialog::OnInitDialog();
+
+        for (int i = 0; i < QUALITY_COUNT; i++) {
+            m_working[i] = m_profiles[i];
+        }
+        LoadToControls();
+        TranslateDialog(this);
+        return TRUE;
+    }
+
+    virtual void OnOK() override
+    {
+        CString err;
+        if (!ReadFromControls(err)) {
+            MessageBox(err, _TR("提示"), MB_ICONWARNING);
+            return;
+        }
+        for (int i = 0; i < QUALITY_COUNT; i++) {
+            m_profiles[i] = m_working[i];
+        }
+        CDialog::OnOK();
+    }
+
+    virtual BOOL OnCommand(WPARAM wParam, LPARAM lParam) override
+    {
+        if (LOWORD(wParam) == IDC_PLEVEL_RESET && HIWORD(wParam) == BN_CLICKED) {
+            ResetToDefaults();
+            return TRUE;
+        }
+        return CDialog::OnCommand(wParam, lParam);
+    }
+};