gitadora: more windowed mode fixes (#819)

## Link to GitHub Issue or related Pull Request, if one exists
User reported

## Description of change

Sometimes the game moved the main window after `CreateWindowExA`
returned but before D3D initialization called
`graphics_capture_initial_window`. During this gap,
`GRAPHICS_HOOKED_WINDOW` was not set, so the placement hooks could not
identify the main window and preserve its monitor override. GITADORA
main, LEFT, and RIGHT windows are now registered immediately after
creation so later placement calls cannot undo their overrides.

This also adds `-gdwsmallsize` and `-gdwsmallpos` for explicitly setting
the SMALL window size and position. Explicit values override the
corresponding monitor-derived geometry, allowing the SMALL window's
10:16 aspect ratio to be preserved instead of stretching it to fill a
monitor.

## Testing

src/spice2x/launcher/launcher.cpp

@@ -1286,6 +1286,14 @@ int main_implementation(int argc, char *argv[]) {
         GRAPHICS_GITADORA_SMALL_MONITOR =
             options[launcher::Options::GitaDoraWindowedSmallMonitor].value_text();
     }
+    if (options[launcher::Options::GitaDoraWindowedSmallSize].is_active()) {
+        GRAPHICS_GITADORA_SMALL_SIZE =
+            options[launcher::Options::GitaDoraWindowedSmallSize].value_text();
+    }
+    if (options[launcher::Options::GitaDoraWindowedSmallPosition].is_active()) {
+        GRAPHICS_GITADORA_SMALL_POS =
+            options[launcher::Options::GitaDoraWindowedSmallPosition].value_text();
+    }
 
     // IIDX/SDVX Windowed Subscreen
     if (options[launcher::Options::spice2x_IIDXWindowedSubscreenSize].is_active()) {