Drawbridges (down, up, automatic), frost spell and obsidian over cooled lava

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

docs/ROADMAP.md

@@ -3,7 +3,7 @@
 Agreed on 2026-11-05. Worked through in this order; every block is committed, pushed and deployed
 on its own. Details not listed here are decided along the way.
 
-## 1. Open items
+## 1. Open items – done (v202611-00035)
 
 1. **Heroes attack every master** – with rival masters or several players, each hero wave marches
    to the heart of the *strongest* living master (most creatures and gold), not only the player's.
@@ -14,7 +14,7 @@ on its own. Details not listed here are decided along the way.
    the reached mission; the host keeps the progress.
 4. **New screenshots** – title demo, language dropdown, co-op campaign.
 
-## 2. Bridges
+## 2. Bridges – done (v202611-00036)
 
 Stone bridges over lava exist already (75 gold per tile).
 
@@ -27,6 +27,9 @@ Stone bridges over lava exist already (75 gold per tile).
 4. **Repairing bridges** – imps repair damaged bridges; knights wear bridges down step by step
    instead of in one blow.
 
+Built as: `src/bridges.rs` (fire, wear, drawbridges, obsidian), the *Drawbridge* tool (click: down → up →
+automatic) and the *Frost* spell (lava → obsidian for 40 s); the frost glow trap keeps lava next to it cooled.
+
 ## 3. The surface world
 
 1. **Surface terrain** – grass, trees, paths, daylight and sky. Trees act like earth: imps fell