Add Changban pursuit scenario

docs/DATA_MODEL.md

@@ -36,6 +36,7 @@ data/scenarios/022_liaoxi_pursuit.json
 data/scenarios/023_white_wolf_mountain.json
 data/scenarios/024_liaodong_pursuit.json
 data/scenarios/025_xinye_advance.json
+data/scenarios/026_changban_pursuit.json
 ```
 
 ## Campaign
@@ -73,7 +74,8 @@ The campaign file defines scenario order, resource paths, and officers who are a
     { "id": "022_liaoxi_pursuit", "title": "Liaoxi Pursuit", "path": "res://data/scenarios/022_liaoxi_pursuit.json" },
     { "id": "023_white_wolf_mountain", "title": "White Wolf Mountain", "path": "res://data/scenarios/023_white_wolf_mountain.json" },
     { "id": "024_liaodong_pursuit", "title": "Liaodong Pursuit", "path": "res://data/scenarios/024_liaodong_pursuit.json" },
-    { "id": "025_xinye_advance", "title": "Xinye Advance", "path": "res://data/scenarios/025_xinye_advance.json" }
+    { "id": "025_xinye_advance", "title": "Xinye Advance", "path": "res://data/scenarios/025_xinye_advance.json" },
+    { "id": "026_changban_pursuit", "title": "Changban Pursuit", "path": "res://data/scenarios/026_changban_pursuit.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 twenty-five-scenario campaign.
+- Next-battle flow exists across the current twenty-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 twenty-five-scenario campaign order exists.
+- Linear twenty-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.
@@ -85,6 +85,7 @@
 - Twenty-third-scenario content exists with White Wolf Mountain, Wuhuan riders, Yuan exile escorts, and 022 branch reactions.
 - Twenty-fourth-scenario content exists with Liaodong pursuit, Yuan fugitives, Liaodong border guards, and 023 branch reactions.
 - Twenty-fifth-scenario content exists with Xinye advance, Liu Bei's rearguard, Jing Province pressure, and 024 branch reactions.
+- Twenty-sixth-scenario content exists with Changban pursuit, Liu Bei's bridge guard, Zhang Fei pressure, and 025 branch reactions.
 
 ## Milestone 5: Presentation