needs: stages - every stage the business named must be a state

Found by simulating a generated site: the owner wrote "they come in,
we go and look at the building, we send a quote", and the generated
machine went open -> quoted. Nothing compared the machine to what the
business said, so it passed. A need may now list its stages as the
business describes them; each must be a state of the bucket and
reachable through the handling group's desk.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L4jrCgLiKKHAEFuZUJjckH

src/needs.rs

@@ -79,6 +79,13 @@ pub struct Need {
     /// What a simulation or a live bucket report counts toward.
     #[serde(default)]
     pub success: Vec<String>,
+    /// Every stage the business said a case goes through, in its own
+    /// order, first to last. Written from how the business describes
+    /// its work, before any state machine exists, so that a machine
+    /// which quietly skips a stage ("we go and look, then we quote"
+    /// becoming open -> quoted) fails instead of passing.
+    #[serde(default)]
+    pub stages: Vec<String>,
 }
 
 fn root() -> String {
@@ -455,6 +462,25 @@ pub fn check(
                 );
             }
         }
+        for stage in &need.stages {
+            if !schema.has_state(stage) {
+                report(
+                    Level::Fail,
+                    format!(
+                        "the business describes a stage {stage:?} that {:?} has no state for",
+                        need.lands_in
+                    ),
+                );
+            } else if !reached.contains(stage) {
+                report(
+                    Level::Fail,
+                    format!(
+                        "stage {stage:?} exists but {:?} is offered no moves that reach it",
+                        need.handled_by
+                    ),
+                );
+            }
+        }
         for state in &need.success {
             if !need.done_when.contains(state) {
                 report(
@@ -841,6 +867,15 @@ mod tests {
         assert_eq!(model["buckets"]["projects"]["initial"], "open");
         assert_eq!(model["personas"][0]["id"], "founder");
 
+        // A stage the business named must exist as a state.
+        file.needs[0].stages = vec!["open".into(), "surveyed".into(), "quoted".into()];
+        assert_eq!(
+            fails(&check(&file, &questions, &aggregates)),
+            vec!["the business describes a stage \"surveyed\" that \"projects\" has no state for"]
+        );
+        file.needs[0].stages = vec!["open".into(), "quoted".into(), "won".into()];
+        assert!(check(&file, &questions, &aggregates).is_empty());
+
         file.needs[0].success = vec!["quoted".to_string()];
         assert_eq!(
             fails(&check(&file, &questions, &aggregates)),