Add Sishui vanguard campaign battle

docs/roadmap.md

@@ -21,11 +21,12 @@ Build a small complete tactical RPG loop that can grow into a longer Romance of
 - Second battle expansion with a larger scrollable map, mixed enemy AI behaviors, minimap navigation, camp progression, and save persistence
 - Third battle expansion path toward Guangzong with a new battlefield, story bridge, campaign step persistence, and title continue support
 - Fourth battle Guangzong main camp confrontation with Zhang Jue, expanded enemy formation, campaign persistence, and anti-Dong Zhuo setup
-- Flow verification script from title through the fourth battle victory and camp save state
+- Fifth battle Sishui Gate vanguard path starting the anti-Dong Zhuo chapter, with campaign persistence and title continue support
+- Flow verification script from title through the fifth battle victory and camp save state
 
 ## Next Steps
 
-1. Start the anti-Dong Zhuo chapter with a story bridge and first coalition-era battle
+1. Build the Gongsun Zan camp chapter after the Sishui Gate vanguard battle
 2. Broaden camp events so bonds, supplies, and equipment choices matter between battles
 3. Apply treasure equipment effects to damage, defense, recovery, and command rules
 4. Add more distinctive victory/defeat branches and optional objectives