fix: UI text overlapping and special character fixes

- Replace special characters with ASCII equivalents
- Fix orbital preview positioning in create/edit tabs
- Fix dropdown positioning in Hohmann tab

src/ui_renderer.cpp

@@ -668,7 +668,7 @@ void render_maneuver_create_tab(SimulationState* sim, UIState* ui_state, int x,
     update_orbital_preview(sim, ui_state);
 
     if (ui_state->maneuver_dialog.show_preview) {
-        Rectangle preview_bounds = {(float)x + 8, (float)current_y + 10, (float)width - 16, 110};
+        Rectangle preview_bounds = {(float)x + 8, (float)current_y + 50, (float)width - 16, 110};
         render_orbital_preview(sim, ui_state, preview_bounds);
     }
 }
@@ -751,7 +751,7 @@ void render_orbital_preview(SimulationState* sim, UIState* ui_state, Rectangle b
     y += 30;
 
     Rectangle status_bounds = {(float)x, (float)y, (float)width, 25};
-    const char* status_text = ui_state->maneuver_dialog.preview_valid ? "✓ All parameters valid" : "✗ Invalid parameters";
+    const char* status_text = ui_state->maneuver_dialog.preview_valid ? "[OK] All parameters valid" : "[X] Invalid parameters";
     GuiLabel(status_bounds, status_text);
 }
 
@@ -824,7 +824,7 @@ void render_maneuver_hohmann_tab(SimulationState* sim, UIState* ui_state, int x,
 
     if (sim->craft_count > 0) {
         static bool edit_mode_spacecraft = false;
-        if (GuiDropdownBox({(float)x + 120, (float)(current_y - 35), (float)(width - 130), 25},
+        if (GuiDropdownBox({(float)x + 120, (float)current_y, (float)(width - 130), 25},
                           ui_state->craft_list_buffer, &ui_state->maneuver_dialog.craft_index, edit_mode_spacecraft)) {
             edit_mode_spacecraft = !edit_mode_spacecraft;
         }
@@ -837,7 +837,7 @@ void render_maneuver_hohmann_tab(SimulationState* sim, UIState* ui_state, int x,
 
     if (sim->body_count > 0) {
         static bool edit_mode_transfer_parent = false;
-        if (GuiDropdownBox({(float)x + 120, (float)(current_y - 35), (float)(width - 130), 25},
+        if (GuiDropdownBox({(float)x + 120, (float)current_y, (float)(width - 130), 25},
                           ui_state->body_dropdown_buffer, &ui_state->maneuver_dialog.transfer_body_index, edit_mode_transfer_parent)) {
             edit_mode_transfer_parent = !edit_mode_transfer_parent;
         }
@@ -850,7 +850,7 @@ void render_maneuver_hohmann_tab(SimulationState* sim, UIState* ui_state, int x,
 
     if (sim->body_count > 0) {
         static bool edit_mode_current_body = false;
-        if (GuiDropdownBox({(float)x + 120, (float)(current_y - 35), (float)(width - 130), 25},
+        if (GuiDropdownBox({(float)x + 120, (float)current_y, (float)(width - 130), 25},
                           ui_state->body_dropdown_buffer, &ui_state->maneuver_dialog.current_body_index, edit_mode_current_body)) {
             edit_mode_current_body = !edit_mode_current_body;
         }
@@ -863,7 +863,7 @@ void render_maneuver_hohmann_tab(SimulationState* sim, UIState* ui_state, int x,
 
     if (sim->body_count > 0) {
         static bool edit_mode_target_body = false;
-        if (GuiDropdownBox({(float)x + 120, (float)(current_y - 35), (float)(width - 130), 25},
+        if (GuiDropdownBox({(float)x + 120, (float)current_y, (float)(width - 130), 25},
                           ui_state->body_dropdown_buffer, &ui_state->maneuver_dialog.target_body_index, edit_mode_target_body)) {
             edit_mode_target_body = !edit_mode_target_body;
         }
@@ -1431,7 +1431,7 @@ void render_maneuver_edit_tab(SimulationState* sim, UIState* ui_state, int x, in
     update_orbital_preview(sim, ui_state);
 
     if (ui_state->maneuver_dialog.show_preview) {
-        Rectangle preview_bounds = {(float)x + 8, (float)current_y + 10, (float)width - 16, 110};
+        Rectangle preview_bounds = {(float)x + 8, (float)current_y + 50, (float)width - 16, 110};
         render_orbital_preview(sim, ui_state, preview_bounds);
     }