Settings take effect with Apply/Close or Save (#134)

* Add a settings draft that holds edits until they are applied

The settings window is to stage its edits and apply them with Apply/Close
or Save instead of writing each one at once. SettingsDraft holds one
pending change per setting, reads through to the stored value, and on
apply writes everything first and then runs each effect key once, in the
order the settings were first changed. Form.committed registers its typed
entry with the draft so a click on Apply cannot lose it.

The spec explains the order and the settings that stay immediate.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Stage the settings tabs' edits and apply them with Apply/Close or Save

Every tab state now reads through the window's draft and stages its edits
there instead of writing ChatPreferences: Station (all but the login
credentials), Log synch, TRX synch, Airscout, Notification, Shortcuts,
Beacon, Message handling and GUI (all but the language). The lists stage
their roster, the committed fields stage what their rule accepts.

Effects stay attached to their settings. The Win-Test listener and the DX
cluster server share one effect for switch and port that brings the running
service in line with the applied state, so applying both restarts it once,
on the new port. The own-QRG follower runs once for both sources.

Apply/Close applies and closes, Save applies and writes, Connect applies
before it connects, so the session uses what the tabs show. A field that
refuses its entry on the way stops the button with the reason shown.

Immediate as before: the login credentials, the language, the colours, the
file chooser, the test spot and the profile and worked-database actions.

Number fields keep the typed text while the staged value comes back as
Compose state; otherwise "1" became "1.0" before the next key.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Ask about unapplied settings when the window is closed

Closing the settings window with its X, or through the Windows menu, while
edits wait in the draft now asks: apply them, discard them, or go back to
the window. Without pending edits the window closes as before. Fields and
list rows still holding a typed entry are committed first, so an entry
typed just before the X counts.

The request only sets Compose state; the window decides on its next frame,
so nothing waits on the event thread. A close from outside -- a profile
switch, the shutdown -- discards the draft: the preferences it belongs to
are about to be replaced.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Document that settings take effect with Apply

PROJECT_CONTEXT records the draft and what stays immediate, the changelog
gets one entry under v1.50, and the configuration manual no longer says
that settings take effect while they are edited.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Repair stored settings once before the settings window is built

The fallback band of the DX cluster was repaired to 144 inside a getter
that runs during composition, and the Win-Test broadcast address was
auto-detected in a tab state's constructor. Both wrote ChatPreferences
past the draft at a moment nobody could see. repairStoredSettings now does
both once, before any tab is built; the tab states only read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Ask before a profile switch or exit, and check fields before applying

A profile switch and the exit dropped pending settings edits silently. They
now go through SettingsWindow.settleThen: with edits pending, the window is
raised and asks Apply / Discard / Back; Apply applies them to the profile
still in force, Back cancels the switch or the exit. The question is Compose
state and the continuation is posted from the dialog's callback, so the
event thread never waits. Without pending edits both go on at once.

Fields are checked before anything is applied: a field still showing text
that does not parse, or that its rule refuses, refuses the apply and is
named in the notice, so the valid edits stay pending and Discard is still
possible. This covers number fields and the guarded external-interface
fields, which used to let Apply go ahead with the last valid value.

Every write and effect of an apply now runs on its own; failures are
collected and reported, a failed write stays pending and skips its effect,
and Save still writes the file when only an effect failed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Check every drafted setting with a real draft, and rename write-through tests

DraftedSettingsTableTest walks every drafted setter of every tab with a
real SettingsDraft: unchanged after the edit, changed after apply,
unchanged after discard. The tab tests run with a draft that applies at
once and cannot tell a drafted setting from one that bypasses the draft.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Document the question on switch and exit, the field checks and the repairs

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Decide the pending-settings question on the event thread, never trap

The question is now a SettingsQuestion decided in settle() on the calling
event thread instead of in the settings window's next frame, so an exit
from the main window does not depend on frames of a minimised settings
window; the window is raised and restored before the dialog is needed.

While a question is open, further requests are ignored: an X no longer
replaces the continuation of an exit or switch with a plain close. Each
continuation of settleThen runs at most once.

A field holding text it refuses no longer traps the operator: the X, the
switch and the exit show the question anyway, with the reason, Apply
disabled and Discard and Back available.

The apply-failure notice keeps the technical detail out of the sentence,
in parentheses after a translated one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

github_docs/en-Configuration.md

@@ -4,7 +4,9 @@
 
 After the first start, the **settings window** opens – this is the central starting point for all configuration. It is recommended to keep the settings window open during operation (e.g. to quickly toggle the beacon on and off).
 
-> **Important**: Use **Save Settings** for functional settings which should remain in effect after the next start. KST4Contest saves layout changes such as window sizes, divider positions and table-column widths automatically. The shared file is `~/.praktiKST/preferences.xml` on Linux and macOS and `%USERPROFILE%\.praktiKST\preferences.xml` (or `C:\Users\<Username>\.praktiKST\preferences.xml`) on Windows.
+> **Important**: Changes in the settings window take effect when you click **Apply/Close prefs** or **Save Settings**; **Connect** applies them first as well. Closing the window, switching the operator profile or exiting with changes pending first asks whether to apply or discard them, or to go back. Colours, the language and the login data on the **Station** tab take effect immediately.
+>
+> Use **Save Settings** for functional settings which should remain in effect after the next start. KST4Contest saves layout changes such as window sizes, divider positions and table-column widths automatically. The shared file is `~/.praktiKST/preferences.xml` on Linux and macOS and `%USERPROFILE%\.praktiKST\preferences.xml` (or `C:\Users\<Username>\.praktiKST\preferences.xml`) on Windows.
 
 ---
 
@@ -158,7 +160,7 @@ TRX synchronisation imports the current frequency from the logging application a
 
 The general listener is intended for logging applications which transmit compatible `RadioInfo` packets. Depending on their individual configuration, this includes UCXLog, N1MM+, QARTest and DXLog.net. QSO and `RadioInfo` packets use the same port configured under **Log sync**, but separate options determine whether KST4Contest processes QSO information, TRX information or both packet types. An automatic QRG source must be enabled and actually supply valid packets; enabling it alone does not update `MYQRG`.
 
-Restart KST4Contest after changing the shared UDP port. Changes to the two QRG-sync checkboxes take effect immediately.
+Restart KST4Contest after changing the shared UDP port. Changes to the two QRG-sync checkboxes take effect as soon as they are applied.
 
 ### Which QRG Is Updated?
 
@@ -356,7 +358,7 @@ This selection does more than reduce network traffic. It also prevents AirScout
 
 ### Applying Changed Settings
 
-The following changes are used for new packets immediately after leaving the input field or changing the checkbox:
+The following changes are used for new packets as soon as they are applied:
 
 - enabling or disabling the AirScout integration,
 - server identifier,
@@ -417,7 +419,7 @@ Further details, including numbers which are deliberately ignored, are described
 
 KST4Contest can forward detected directional opportunities to logging software as DX cluster spots. A frequency recognised in the chat can therefore appear directly in the logger's band map without being entered manually.
 
-The **Enable the local DX Cluster server …** checkbox starts or stops the local TCP server. When KST4Contest is connected to the chat, the change takes effect immediately.
+The **Enable the local DX Cluster server …** checkbox starts or stops the local TCP server. When KST4Contest is connected to the chat, the change takes effect as soon as it is applied.
 
 The following settings and controls belong to the local DX cluster output:
 
@@ -514,7 +516,7 @@ The order of the table determines the order of the buttons in the main window. M
 3. To remove an entry, delete its complete contents and confirm with `Enter`.
 4. Use **Move selected up** and **Move selected down** to change the position of the selected entry.
 
-Changes appear in the main window immediately. Use **Save Settings** afterwards if they should remain available after the next program start.
+Applied changes appear in the main window at once. Use **Save Settings** afterwards if they should remain available after the next program start.
 
 ---
 
@@ -563,7 +565,7 @@ The snippet list is edited in the same way as the shortcut list:
 4. Confirming an empty entry removes it.
 5. **Move selected up** and **Move selected down** change both the displayed order and the assignment to `Ctrl+1` through `Ctrl+0`.
 
-The context menus and keyboard mappings are updated immediately. Use **Save Settings** afterwards to store the modified list permanently.
+The context menus and keyboard mappings are updated as soon as the change is applied. Use **Save Settings** afterwards to store the modified list permanently.
 
 The complete list of available placeholders and their limitations is described under [Macros and Variables](en-Macros-and-Variables).
 
@@ -914,7 +916,7 @@ Manage the list as follows:
 
 The entered value may contain a visible KST suffix or portable components. KST4Contest normalises it to the base callsign before storing it. Different variants of the same base callsign are therefore treated as duplicates.
 
-Changes to the list take effect immediately. Press **Save Settings** afterwards to retain them. The base callsigns are stored in `preferences.xml` and restored at the next program start.
+Changes to the list take effect as soon as they are applied. Press **Save Settings** afterwards to retain them. The base callsigns are stored in `preferences.xml` and restored at the next program start.
 
 > Base-callsign monitoring across KST suffixes is included from v1.42 onwards.
 
@@ -929,7 +931,7 @@ Two optional additions to the band columns can be enabled or disabled in the **G
 - **Show "o" in band columns …** displays an `o` if the four-character grid square has already been worked on the relevant band. Disabling the option does not delete any database records; it only hides the additional indicator in the band columns. `wkdany` is unaffected.
 - **Show "a" in band columns …** distinguishes a completely new callsign from a band opportunity involving a callsign already worked elsewhere. When disabled, both cases are displayed as `B+`. The band-opportunity calculation itself remains unchanged.
 
-Changes are reflected in the current user interface immediately. Click **Save Settings** afterwards if they should persist after the next start.
+Applied changes are reflected in the current user interface at once. Click **Save Settings** afterwards if they should persist after the next start.
 
 ![GUI settings for band-column hints](client_settings_window_gui.png)
 
@@ -1003,7 +1005,7 @@ The **Profiles** tab in the settings window lists all profiles with their name,
 
 ### Switching profiles while running
 
-**File > Switch operator profile...**, or the button on the **Profiles** tab, switches without restarting the program. After a confirmation the ON4KST connection is closed and the user interface is rebuilt with the settings and layout of the selected profile. The layout of the previous profile is saved first; settings not yet confirmed with **Save Settings** are lost.
+**File > Switch operator profile...**, or the button on the **Profiles** tab, switches without restarting the program. After a confirmation the ON4KST connection is closed and the user interface is rebuilt with the settings and layout of the selected profile. If the settings window still holds changes that were not applied, KST4Contest first asks whether to apply them to the current profile, discard them, or cancel the switch. The layout of the previous profile is saved first; settings not yet confirmed with **Save Settings** are lost.
 
 Once more than one profile exists, the main window title also shows the profile name.
 
@@ -1015,7 +1017,7 @@ As before, the ON4KST password is stored in clear text in the `preferences.xml`
 
 ## Dark Mode (from v1.26)
 
-Each operator profile sets its own startup colour scheme: on the **GUI** tab under **Design**, choose **Light mode** or **Dark mode**. The choice takes effect immediately and is stored in the profile's `preferences.xml` with **Save Settings**.
+Each operator profile sets its own startup colour scheme: on the **GUI** tab under **Design**, choose **Light mode** or **Dark mode**. The choice takes effect when it is applied and is stored in the profile's `preferences.xml` with **Save Settings**.
 
 For a quick change during operation, use **Windows → Use dark mode design** and **Windows → Use default mode design**. This switch only lasts until the next start or profile switch; after that the setting on the **GUI** tab applies again.
 
@@ -1023,7 +1025,7 @@ For a quick change during operation, use **Windows → Use dark mode design** an
 
 ## Saving Settings
 
-**Save Settings** stores functional settings and the complete current layout. Changes to window sizes and positions, relevant dividers, managed table-column widths and the **Group nearby stations** map setting are also saved automatically after a short delay. Any pending layout update is written when the programme exits.
+**Save Settings** applies pending changes first, then stores functional settings and the complete current layout. Changes to window sizes and positions, relevant dividers, managed table-column widths and the **Group nearby stations** map setting are also saved automatically after a short delay. Any pending layout update is written when the programme exits.
 
 - Storage location: `~/.praktiKST/preferences.xml` on Linux and macOS and `%USERPROFILE%\.praktiKST\preferences.xml` (or `C:\Users\<Username>\.praktiKST\preferences.xml`) on Windows
 - The automatic layout writer does not copy functional changes which have not yet been confirmed with **Save Settings**.