Block scripts and triggers: data model, Rhai translation and runtime

Editor missions keep a painted map or roll a random map per campaign run,
leave out goals they cannot have, and run their triggers in the fixed step.

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

src/game.rs

@@ -541,6 +541,10 @@ pub struct Game {
     #[serde(default)]
     pub mission: Option<MissionState>, // campaign mission (None: free game)
     #[serde(default)]
+    pub script: Option<crate::mscript::ScriptState>, // block scripts of an editor mission
+    #[serde(default)]
+    pub objective: Option<String>, // the objective a mission script set
+    #[serde(default)]
     pub rivals: Vec<crate::rival::Rival>, // AI dungeon masters
     #[serde(default = "yes")]
     pub gate_on: bool, // free game: the humans' gate exists
@@ -866,6 +870,8 @@ impl Game {
             towers_razed: 0,
             contested: Vec::new(),
             mission: None,
+            script: None,
+            objective: None,
             rivals: Vec::new(),
             gate_on: true,
             springs: 0,
@@ -1340,6 +1346,11 @@ impl Game {
             self.switch_to(side);
             self.sync_treasury();
         }
+        // mission scripts: always from the first player's side, the same on every computer
+        if self.script.is_some() {
+            self.switch_to(0);
+            self.run_scripts();
+        }
         let local = self.local_side;
         self.switch_to(local);
     }
@@ -2729,7 +2740,7 @@ impl Game {
     }
 
     // the ground of tile i turned into river (bridge removed): units on it fall in
-    fn ground_lost(&mut self, i: usize) {
+    pub(crate) fn ground_lost(&mut self, i: usize) {
         let lava = self.map.t[i].kind == Kind::Lava;
         let (x, y) = xy(i);
         for j in 0..self.ents.len() {
@@ -5231,6 +5242,7 @@ impl Game {
             }
             self.fx(2, x, y, 0.0, 0.0, 0.3, 0xffffffff);
             self.sfx(Sfx::Slap, x, y);
+            self.script_event(crate::mscript::ScriptEvent::Slap);
             return 1;
         }
         if self.ents[j].captive != 0 {