Open secondary windows on the main window's screen (#59) (#135)

* Open secondary windows on the main window's screen (#59)

Every Compose window but the main one went to the platform's default
position, which on a multi-monitor desk is the primary screen - the
station map could open on a monitor that was switched off. They now open
centred on the screen the main window is on, with their size clamped to
that screen's usable area (insets considered). A window the operator
moved during the session reopens there, as long as its title bar can
still be grabbed on a connected screen; otherwise it falls back to the
main window's screen. The position lives only in the window's host and
is never persisted. ComposeAlert dialogs and the profile picker are
centred the same way once the main window exists.

The rule is a pure function (WindowPlacement) with 18 unit tests; the
AWT side (WindowPlacementOnScreen) only reads the screens and the main
window's bounds on the event thread. The clamped opening size of a
secondary window is not written back, so the stored size survives a
smaller screen.

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

* Track window moves reliably and keep remembered windows on screen (#59)

Review fixes for the window placement:

- Once a window has left the tolerance around its opening position,
  every later position is remembered. Before, the anchor was never
  re-set, so dragging away and back to near the opening spot left the
  stale far position remembered.
- A window the host did not place (opened before the main window
  exists) only trusts its anchor once two consecutive reports lie
  within the tolerance, so a provisional position followed by the
  window manager's placement jump is no longer taken as the operator's
  move.
- A remembered position is shifted the least distance that puts the
  (clamped) window wholly inside the usable area of the screen holding
  its title bar, as the KDoc promised.

The move rule moves into a pure MoveTracker with 5 tests; WindowPlacement
gains keptWithin and 2 more tests.

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

* Keep window positions across restarts as an opt-in; fit windows to small screens (#59)

A new GUI tab option, off by default, keeps the position the operator last
moved each window to, the main window included. It is stored per window
with the bounds of the screen it was on, written by the layout autosave,
and restored only when a screen with exactly those bounds is connected
again; otherwise the session rule applies. Only operator moves are
stored, never window manager nudges, so a restored window cannot drift.

An open window that rests on a screen too small for it is now cut down
to that screen's usable area, and the station map's 900x600 minimum is
capped to the smallest connected screen, so 640x480 monitors stay usable.

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

* Never store a size or position the host fitted a window to (#59)

The cut-down to a small screen was written back as the stored size
(main window via onResized, others via the tracker) and counted as an
operator move. The host now records its own fit: that size is not
written back, and that position re-anchors the move tracker instead of
being stored. A main window opened at a stored position skips its
opening size like the other windows, since it may be clamped too.
The opt-in gate moves into PreferencesWindowPositionMemory, with tests.

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

* Match the fit echo with tolerance and consume it once (#59)

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

---------

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

github_docs/en-Changelog.md

@@ -42,6 +42,8 @@ Several operators sharing one computer can now use their own callsigns, locators
 
 - **Settings take effect with Apply:** changes in the settings window no longer take effect while they are typed, but with **Apply/Close prefs** or **Save settings**; **Connect** applies them first as well. This also works during a running session. 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, language and the login data on the **Station** tab still take effect immediately.
 
+- **Windows open on the main window's screen:** the station map, monitor, settings, update window, top candidates and the notice dialogs used to open on the primary screen, even when the main window was on another one or the primary screen was switched off. They now open centred on the screen the main window is currently on. A window that was moved during the running session reopens there next time, as long as its title bar can still be reached on a connected screen. With the new option **Reopen windows across restarts where they were last moved to** on the **GUI** tab (off by default), the main window and all other windows also keep their position across restarts; a stored position is only used when the very same screen (same place and resolution) is connected again. A window larger than the screen is reduced to its usable area, also when it is moved onto a smaller screen later, for example a 640x480 monitor; the stored window size stays unchanged. This fixes [Issue #59](https://github.com/praktimarc/kst4contest/issues/59).
+
 ### Fixed
 
 - **Consistent font size:** on macOS and Linux JavaFX uses a slightly larger default font than on Windows, which cut off labels in fixed-size controls. KST4Contest now uses the same base font size on all systems; nothing changes on Windows.