Add Weishui crossing scenario

docs/DATA_MODEL.md

@@ -46,6 +46,7 @@ data/scenarios/032_jiangling_rearguard.json
 data/scenarios/033_tong_pass_vanguard.json
 data/scenarios/034_ma_chao_counterstroke.json
 data/scenarios/035_weishui_camps.json
+data/scenarios/036_weishui_crossing.json
 ```
 
 ## Campaign
@@ -93,7 +94,8 @@ The campaign file defines scenario order, resource paths, and officers who are a
     { "id": "032_jiangling_rearguard", "title": "Jiangling Rearguard", "path": "res://data/scenarios/032_jiangling_rearguard.json" },
     { "id": "033_tong_pass_vanguard", "title": "Tong Pass Vanguard", "path": "res://data/scenarios/033_tong_pass_vanguard.json" },
     { "id": "034_ma_chao_counterstroke", "title": "Ma Chao Counterstroke", "path": "res://data/scenarios/034_ma_chao_counterstroke.json" },
-    { "id": "035_weishui_camps", "title": "Weishui Camps", "path": "res://data/scenarios/035_weishui_camps.json" }
+    { "id": "035_weishui_camps", "title": "Weishui Camps", "path": "res://data/scenarios/035_weishui_camps.json" },
+    { "id": "036_weishui_crossing", "title": "Weishui Crossing", "path": "res://data/scenarios/036_weishui_crossing.json" }
   ]
 }
 ```

docs/ROADMAP.md

@@ -21,7 +21,7 @@
 - Destination victory conditions and objective map markers exist.
 - Turn-limit conditions and HUD turn-limit display exist.
 - Victory reward summary is visible.
-- Next-battle flow exists across the current thirty-five-scenario campaign.
+- Next-battle flow exists across the current thirty-six-scenario campaign.
 - Campaign completion and new-campaign reset exist.
 - Reward inventory can be brought into the next battle.
 
@@ -52,7 +52,7 @@
 - Party roster persistence has a first save-file skeleton.
 - Level, experience, and equipment persistence.
 - Chapter selection and save/load.
-- Linear thirty-five-scenario campaign order exists.
+- Linear thirty-six-scenario campaign order exists.
 - Save reset exists.
 - Victory rewards, consumable counts, equipment stock, and equipped gear persist.
 - A basic pre-battle shop with scenario-specific stock exists. Sell-back and richer item management are still planned.
@@ -95,6 +95,7 @@
 - Thirty-third-scenario content exists with Tong Pass vanguard pressure, Ma Chao's riders, western pass control, and 032 branch reactions.
 - Thirty-fourth-scenario content exists with Ma Chao's counterstroke, Tong Pass fortification pressure, Han Sui alliance tension, and 033 branch reactions.
 - Thirty-fifth-scenario content exists with Wei River camp pressure, Ma Chao river assaults, Han Sui mistrust, and 034 branch reactions.
+- Thirty-sixth-scenario content exists with Wei River crossing pressure, Guanzhong foothold stakes, western alliance strain, and 035 branch reactions.
 
 ## Milestone 5: Presentation