Move the synergy catalog from the run HUD to the pause menu

The purple Combos button lived in the run HUD button_area; move it to a
"Combos" row in the pause menu (Escape > under Settings, before
restart_button) so the play screen stays clear. Same overlay, same tabs;
Mods > Combo Advisor is unchanged.

restart_button is an id vanilla only builds during a run, so the row never
reaches the main menu. Because the pause menu builds its node list as a table
constructor with conditional entries (an unseeded run leaves a hole at the
seed row's index), find_trail/insert_node walk and shift by explicit numeric
key rather than ipairs/table.insert.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+### Changed
+- The synergy catalog now opens from the **pause menu** (Escape > Combos, under
+  Settings) instead of a button in the run HUD, which keeps the play screen
+  clear. Same overlay, same tabs; Mods > Combo Advisor is unchanged.
+
 ### Fusion Jokers integration
 - When [Fusion Jokers](https://github.com/wingedcatgirl/Fusion-Jokers) is
   installed, hovering any joker that is a fusion component names the fusion it